The Big Bang Theory (2007)

The Big Bang Theory (2002 - 2014)

TV14 Seasons 1 - 8 Comedy

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8.7/10

IMDB

4.5/5

Vudu

Leonard and Sheldon are brilliant physicists. But none of that genius helps them interact with people, especially women. All this begins to change when a free-spirited beauty named Penny moves in next door.

Written by Chuck Lorre, Bill Prady

Starring
Johnny Galecki
,
Jim Parsons
,
Kaley Cuoco
,
Simon Helberg
,
Kunal Nayyar

Seasons:

1 2 3 4 5 6 7 8

Summary

Episode 1

The Big Bang Theory: Pilot (2007)
23 min
In the series premiere, when Leonard and Sheldon meet Penny, Leonard is immediately interested in her. But Sheldon feels his friend is chasing a dream he'll never catch.
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Episode 2

The Big Bang Theory: The Big Bran Hypothesis (2007)
22 min
After Leonard tries to do a favor for Penny, Sheldon ruins the plan. Leonard volunteers to sign for a package, hoping to make a good impression on Penny.
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Episode 3

The Big Bang Theory: The Fuzzyboots Corollary (2007)
22 min
Leonard is depressed to learn that Penny is dating someone. As a result, encouraged by his friends and fellow scientists, Leonard actually summons the nerve to ask a woman out on a date.
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Episode 4

The Big Bang Theory: The Luminous Fish Effect (2007)
21 min
After being fired from his job, Sheldon attempts to explore the "dreadful" life beyond physics. But his initial thrill of shopping with Penny devolves over time to him weaving ponchos as a shut-in, forcing Leonard to call on Sheldon's mother, Mary.
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Episode 5

The Big Bang Theory: The Hamburger Postulate (2007)
21 min
After sensing that his pursuit of Penny isn't going anywhere, Leonard agrees to an unexpected sexual encounter with fellow scientist Leslie Winkle. The one-night stand throws Leonard and Sheldon deep into uncharted social waters.
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Episode 6

The Big Bang Theory: The Middle Earth Paradigm (2007)
21 min
The socially stunted guys are nervous when Penny invites them to a party she's hosting.
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Episode 7

The Big Bang Theory: The Dumpling Paradox (2007)
22 min
When Wolowitz seduces Penny's friend and ends up sleeping with her in Penny's apartment, Penny sleeps on Leonard and Sheldon's couch.
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Episode 8

The Big Bang Theory: The Grasshopper Experiment (2007)
21 min
Koothrappali becomes overwhelmed when his parents arrange a blind date for him, but he discovers he actually can talk to a member of the opposite sex after a few drinks.
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Episode 9

The Big Bang Theory: The Cooper-Hofstadter Polarization (2008)
20 min
Sheldon and Leonard are invited to present their joint findings at a physics conference, but Sheldon refuses. Penny steps in to mediate, but this only deepens the rift between the two best friends.
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Episode 10

The Big Bang Theory: The Loobenfeld Decay (2008)
21 min
After hearing Penny sing, Leonard lies to avoid seeing her perform. Sheldon goes one step further with a more elaborate lie, leading to the appearance of his nonexistent cousin.
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Episode 11

The Big Bang Theory: The Pancake Batter Anomaly (2008)
22 min
When Sheldon gets sick, Leonard and the boys know what is in store for them and avoid him like the plague; this leaves an unsuspecting Penny to nurse the world's worst patient back to health.
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Episode 12

The Big Bang Theory: The Jerusalem Duality (2008)
21 min
When Leonard and Sheldon meet a teenage physics prodigy, Sheldon is distraught that the boy genius is younger and smarter, and crafts a plan to derail the young prodigy's research.
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Episode 13

The Big Bang Theory: The Bat Jar Conjecture (2008)
22 min
The guys kick Sheldon off the team for the Physics Bowl and enlist his nemesis Leslie Winkle to take his place.
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Episode 14

The Big Bang Theory: The Nerdvana Annihilation (2008)
20 min
When Leonard and the guys buy a time-machine prop from a classic 1960 movie, its arrival creates problems for Penny, and she tells the boys that their obsession with comics and toys is "pathetic."
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Episode 15

The Big Bang Theory: The Shiksa Indeterminacy (2008)
22 min
Leonard, Wolowitz, and Koothrappali all become smitten with Sheldon's twin sister, Missy, and Leonard devises a plan to eliminate his rivals. The plan backfires, however, when Sheldon declares he will decide whom his sister dates.
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Episode 16

The Big Bang Theory: The Peanut Reaction (2008)
20 min
When Penny learns that Leonard doesn't celebrate birthdays, she attempts to throw him a surprise party; she is sidetracked by Sheldon, however, who unexpectedly gets to live out one of his greatest fantasies at an electronics store.
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Episode 17

The Big Bang Theory: The Tangerine Factor (2008)
21 min
When Penny breaks up with her boyfriend, Leonard finally gets up the courage to ask her out on a real date. When she says yes, each seeks the "wisdom" of a reluctant advisor -- Sheldon.
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Summary

Creator/producers Chuck Lorre and Bill Prady make comedy a science with the second big season of THE BIG BANG THEORY that makes room for new series regular Sara Gilbert. Check out the physics of funny!

Episode 1

The Big Bang Theory: The Bad Fish Paradigm (2008)
22 min
In the second season premiere, after her first date with Leonard goes awry, Penny finds an unwilling confidant in Leonard's anti-social roommate, Sheldon.
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Episode 2

The Big Bang Theory: The Codpiece Topology (2008)
22 min
When Leonard sees Penny with a handsome new guy, he enters into a rebound relationship with Sheldon's nemesis, Leslie Winkle).
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Episode 3

The Big Bang Theory: The Barbarian Sublimination (2008)
22 min
Sheldon creates a monster when he introduces Penny to the world of online gaming. Especially when her addiction wreaks havoc on his life.
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Episode 4

The Big Bang Theory: The Griffin Equivalency (2008)
22 min
Newly famous because of an article in a magazine, Raj gets an inflated ego and makes a disastrous play for Leonard s longtime crush, Penny.
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Episode 5

The Big Bang Theory: The Euclid Alternative (2008)
20 min
Leonard and his friends stage an intervention to make Sheldon confront his longstanding fear of driving.
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Episode 6

The Big Bang Theory: The Cooper-Nowitzki Theorem (2008)
21 min
A young grad students attraction to Sheldon confuses everyone including Sheldon himself.
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Episode 7

The Big Bang Theory: The Panty Pinata Polarization (2008)
22 min
Sheldon and Penny engage in a battle of wills as Penny vows to get revenge on Sheldon when he bans her from the apartment for a series of petty infractions.
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Episode 8

The Big Bang Theory: The Lizard-Spock Expansion (2008)
21 min
Wolowitz thinks he's found the love of his life until she meets Leonard.
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Episode 9

The Big Bang Theory: The White Asparagus Triangulation (2008)
21 min
Sheldon can barely contain his joy when Leonard starts dating a woman who meets Sheldon's exacting standards.
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Episode 10

The Big Bang Theory: The Vartabedian Conundrum (2008)
22 min
Leonard just can't say no. When his relationship with new girlfriend, Stephanie starts moving too fast, Leonard turns to Penny for advice.
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Episode 11

The Big Bang Theory: The Bath Item Gift Hypothesis (2008)
21 min
Leonards handsome colleague starts dating Penny. And Leonards friends are being tormented by Sheldon's obsession with gift- giving etiquette.
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Episode 12

The Big Bang Theory: The Killer Robot Instability (2009)
22 min
When Pennys comment about Wolowitzs love life sends him into a depressed stupor, his friends lose their most important teammate in an upcoming fighting robot competition.
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Episode 13

The Big Bang Theory: The Friendship Algorithm (2009)
22 min
Socially awkward Sheldon develops a scientific procedure for making friends.
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Episode 14

The Big Bang Theory: The Financial Permeability (2009)
22 min
Sheldon's "simple" solution to Penny's financial problem leads to a confrontation between Leonard and Penny's hulking ex- boyfriend, Kurt.
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Episode 15

The Big Bang Theory: The Maternal Capacitance (2009)
21 min
A disastrous visit from Mrs. Hofstadter brings Leonard and Penny closer together.
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Episode 16

The Big Bang Theory: The Cushion Saturation (2009)
22 min
A paintball game has surprising consequences for Leonard and his friends when it leads to a fight between Penny and Sheldon - and romance for Wolowitz and Leslie.
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Episode 17

The Big Bang Theory: The Terminator Decoupling (2009)
22 min
A train trip to San Francisco takes a major detour when Leonard, Sheldon, Wolowitz and Raj discover that beautiful sci-fi actress SUMMER GLAU is onboard.
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Episode 18

The Big Bang Theory: The Work Song Nanocluster (2009)
21 min
Penny's home hair products business becomes a complete nightmare when a caffeine-addled Sheldon takes over.
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Episode 19

The Big Bang Theory: The Dead Hooker Juxtaposition (2009)
21 min
There's a new queen bee in the building! Penny develops a rivalry with a sexy female neighbor moves in to the building and threatens to become the "new Penny."
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Episode 20

The Big Bang Theory: The Hofstadter Isotope (2009)
21 min
While Stuart, a fellow comic book-loving pal of the guys, romances Penny, Leonard and Wolowitz venture out into the world of "Ladies' Night" at a local bar.
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Episode 21

The Big Bang Theory: The Vegas Renormalization (2009)
22 min
The boys go to Vegas, leaving Sheldon's locked out at home.
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Episode 22

The Big Bang Theory: The Classified Materials Turbulence (2009)
19 min
Penny makes a surprising revelation about Leonard on her second date with Stuart. And, Wolowitz enlists his friends' help when he discovers a design flaw in his NASA project.
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Episode 23

The Big Bang Theory: The Monopolar Expedition (2009)
22 min
Leonard and Penny reconsider their feelings for one another, when Leonard and his friends decide to spend the summer working - at the North Pole.
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Episode 24

Season 2, Episode 7: The Panty Pinata Polarization (2008)
21 min
Sheldon and Penny engage in a battle of wills as Penny vows to get revenge on Sheldon when he bans her from the apartment for a series of petty infractions.
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Episode 25

Season 2, Episode 8: The Lizard-Spock Expansion (2008)
20 min
Wolowitz (series regular SIMON HELBERG) thinks he's found the love of his life (guest star SARA RUE) until she meets Leonard.
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Episode 26

Season 2, Episode 9: The White Asparagus Triangulation (2008)
21 min
Sheldon can barely contain his joy when Leonard starts dating a woman (SARA RUE) who meets Sheldon's exacting standards.
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Episode 27

Season 2, Episode 10: The Vartabedian Conundrum (2008)
21 min
Leonard just can't say no. When his relationship with new girlfriend, Stephanie starts moving too fast, Leonard turns to Penny for advice.
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Episode 28

Season 2, Episode 11: The Bath Item Gift Hypothesis (2009)
21 min
Leonards handsome colleague starts dating Penny. And Leonards friends are being tormented by Sheldon's obsession with gift-giving etiquette.
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Episode 29

Season 2, Episode 12: The Killer Robot Instability (2009)
21 min
When Pennys comment about Wolowitzs love life sends him into a depressed stupor, his friends lose their most important teammate in an upcoming fighting robot competition.
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Episode 30

Season 2, Episode 13: The Friendship Algorithm (2009)
21 min
Socially awkward Sheldon develops a scientific procedure for making friends.
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Episode 31

Season 2, Episode 14: The Financial Permeability (2009)
21 min
Sheldon's "simple" solution to Penny's financial problem leads to a confrontation between Leonard and Penny's hulking ex-boyfriend, Kurt (guest star BRIAN PATRICK WADE).
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Episode 32

Season 2, Episode 15: The Maternal Capacitance (2009)
20 min
A disastrous visit from Mrs. Hofstadter (special guest star CHRISTINE BARANSKI) brings Leonard and Penny closer together.
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Episode 33

Season 2, Episode 16: The Cushion Saturation (2009)
21 min
A paintball game has surprising consequences for Leonard and his friends when it leads to a fight between Penny and Sheldon – and romance for Wolowitz and Leslie.
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Episode 34

Season 2, Episode 17: The Terminator Decoupling (2009)
21 min
A train trip to San Francisco takes a major detour when Leonard, Sheldon, Wolowitz and Raj discover that beautiful sci-fi actress SUMMER GLAU ("Terminator: The Sarah Connor Chronicles") is onboard. Nobel Laureate for Physics and "Big Bang" theorist, Dr. George Smoot also makes a cameo.
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Episode 35

Season 2, Episode 18: The Work Song Nanocluster (2009)
20 min
Penny's home hair products business becomes a complete nightmare when a caffeine-addled Sheldon takes over.
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Episode 36

Season 2, Episode 19: The Dead Hooker Juxtaposition (2009)
20 min
There's a new queen bee in the building! Penny develops a rivalry with a sexy female neighbor moves in to the building and threatens to become the "new Penny."
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Episode 37

Season 2, Episode 20: The Hofstadter Isotope (2009)
20 min
While Stuart (guest star KEVIN SUSSMAN), a fellow comic book-loving pal of the guys, romances Penny, Leonard and Wolowitz venture out into the world of "Ladies' Night" at a local bar.
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Episode 38

Season 2, Episode 21: The Vegas Renormalization (2009)
21 min
Leonard and Koothrappali take a heartbroken Wolowitz to Las Vegas, leaving Sheldon locked out of his apartment and forced to bunk with Penny.
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Episode 39

Season 2, Episode 22: The Classified Materials Turbulence (2009)
18 min
Things begin to look up for Leonard when Penny makes a surprising revelation on her second date with Stuart (guest star KEVIN SUSSMAN). Meanwhile, Wolowitz enlists his friends' help when he discovers a critical design flaw in his project for NASA.
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Episode 40

Season 2, Episode 23: The Monopolar Expedition (2009)
21 min
On the second season finale, Leonard and Penny reconsider their feelings for one another. When Leonard and his friends decide to spend the summer working – at the North Pole – Penny is conflicted.
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Episode 41

Season 3, Episode 1: The Electric Can Opener Fluctuation (2009)
21 min
On the third season premiere, Sheldon (series star JIM PARSONS) flees back to Texas in disgrace when he learns that the guys tampered with his arctic expedition data – forcing his friends to follow him, and threatening Leonard's (series star JOHNNY GALECKI) hopes for a romantic encounter with Penny (series star KALEY CUOCO).
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Episode 42

Season 3, Episode 2: The Jiminy Conjecture (2009)
21 min
Leonard and Penny struggle to recover from an awkward first hookup, while Sheldon and Howard (series star SIMON HELBERG) stake their best comic books on a bet to determine the species of a cricket. LEWIS BLACK guest stars as an entymologist who settles the high-stakes bet.
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Episode 43

Season 3, Episode 3: The Gothowitz Deviation (2010)
20 min
Howard and Raj (series star KUNAL NAYYAR) visit a Goth nightclub to pick up women, while Sheldon attempts to build a better Penny using chocolate-based behavior modification.
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Episode 44

Season 3, Episode 4: The Pirate Solution (2010)
21 min
Raj must find a new job or be sent back to India. Sheldon, however, has a solution – which leaves Leonard and Penny dealing with Howard as third wheel.
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Episode 45

Season 3, Episode 5: The Creepy Candy Coating Corollary (2010)
21 min
While Sheldon settles a score with his nemesis, Star Trek: The Next Generation's WIL WHEATON (guest starring as himself), Wolowitz begs Leonard to get Penny to set him up with one of her friends.
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Episode 46

Season 3, Episode 6: The Cornhusker Vortex (2010)
19 min
Sheldon teaches Leonard how to understand football, while a kite- fighting incident threatens Howard and Raj's friendship.
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Episode 47

Season 3, Episode 7: The Guitarist Amplification (2010)
19 min
Sheldon plays the peacemaker when an argument between Leonard and Penny proves "inconvenient" to him.
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Episode 48

Season 3, Episode 8: The Adhesive Duck Deficiency (2010)
20 min
With Leonard, Howard and Raj away camping in the desert, an injured Penny has only Sheldon to rely on.
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Episode 49

Season 3, Episode 9: The Vengeance Formulation (2010)
19 min
After he's humiliated on National Public Radio, Sheldon vows to destroy Kripke (guest star JOHN ROSS BOWIE), and the guys help Sheldon exact his revenge. Meanwhile, Wolowitz tries not to destroy his new relationship with Bernadette (guest star MELISSA RAUCH). KATEE SACKHOFF (Battlestar Galactica) makes a cameo as Wolowitz's dream girl.
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Episode 50

Season 3, Episode 10: The Gorilla Experiment (2010)
21 min
Sheldon takes on his greatest challenge when he attempts to help Penny understand physics, and Wolowitz becomes jealous when Leonard starts hanging out with his new girlfriend.
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Episode 51

Season 3, Episode 11: The Maternal Congruence (2010)
19 min
A visit from Leonard's mother (guest star CHRISTINE BARANSKI) delights Sheldon and horrifies Leonard.
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Episode 52

Season 3, Episode 12: The Psychic Vortex (2010)
19 min
While Sheldon and Koothrappali attend a university mixer, Leonard is upset to discover that Penny believes in psychics. DANICA McKELLAR (The Wonder Years) guest stars as the object of Raj's attraction.
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Episode 53

Season 3, Episode 13: The Bozeman Reaction (2010)
20 min
When their apartment is robbed, Leonard and Sheldon turn to their friends to create a state-of-the-art security system – and Sheldon struggles to cope.
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Episode 54

Season 3, Episode 14: The Einstein Approximation (2010)
18 min
Suffering from a case of "physicist's block," Sheldon's search for the answer to a physics problem leads him to work at the Cheesecake Factory with Penny.
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Episode 55

Season 3, Episode 15: The Large Hadron Collision (2010)
21 min
It's Valentine's Day, and Leonard can only bring one guest on a trip to see CERN's Large Hadron Collider (the world's largest and highest energy particle accelerator) in Switzerland. Will it be Sheldon or Penny?
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Episode 56

Season 3, Episode 16: The Excelsior Acquisition (2010)
21 min
Sheldon misses his chance to meet comic book legend STAN LEE (as himself) when he winds up in traffic court after he gets a ticket because of Penny.
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Episode 57

Season 3, Episode 17: The Precious Fragmentation (2010)
20 min
When the guys find a rare movie prop ring from The Lord of the Rings at a garage sale, it threatens to tear them apart – forcing them to choose the ring or their friendship.
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Episode 58

Season 3, Episode 18: The Pants Alternative (2010)
21 min
Sheldon's friends come to his aid when his fear of public speaking stands between him and a coveted award.
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Episode 59

Season 3, Episode 19: The Wheaton Recurrence (2010)
21 min
A fight between Leonard and Penny threatens their relationship, while Sheldon battles WIL WHEATON (guest starring as Himself) in bowling.
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Episode 60

Season 3, Episode 20: The Spaghetti Catalyst (2010)
20 min
When Leonard and Penny aren't speaking, Sheldon goes to extremes to keep them both happy and gets caught in a lie.
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Episode 61

Season 3, Episode 21: The Plimpton Stimulation (2010)
21 min
Leonard and Sheldon compete for the attention of a famous female physicist – Dr. Elizabeth Plimpton (guest star JUDY GREER).
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Episode 62

Season 3, Episode 22: The Staircase Implementation (2010)
20 min
Leonard tells Penny the story of how he met Sheldon for the first time…and what happened to the elevator.
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Episode 63

Season 3, Episode 23: The Lunar Excitation (2010)
20 min
In the third season finale, Wolowitz and Koothrappali search for Sheldon's perfect match online – and find Sheldon's ideal woman (guest star MAYIM BIALIK). Meanwhile, Penny worries that dating Leonard has ruined her for normal guys.
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Episode 64

Season 4, Episode 1: The Robotic Manipulation (2010)
21 min
On the fourth season premiere, Penny (series star KALEY CUOCO) finds herself along for the ride on Sheldon's (series star JIM PARSONS) first date ever. Meanwhile, Wolowitz (series star SIMON HELBERG) finds a new use for a robotic arm. MAYIM BIALIK guest stars as Sheldon's date, Amy Fowler.
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Episode 65

Season 4, Episode 2: The Cruciferous Vegetable Amplification (2010)
20 min
When Sheldon realizes he won't live long enough to download his consciousness into a robot body, he attempts to extend his lifespan. Apple Co-Founder STEVE WOZNIAK guest stars as Himself.
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Episode 66

Season 4, Episode 3: The Zazzy Substitution (2010)
21 min
The guys are concerned as Sheldon searches for an alternative to human companionship after he and Amy (MAYIM BIALIK) break up. LAURIE METCALF reprises her role as Sheldon's mother.
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Episode 67

Season 4, Episode 4: The Hot Troll Deviation (2010)
19 min
An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work. Battlestar Galactica's KATEE SACKHOFF and Star Trek's GEORGE TAKEI guest star as themselves as Wolowitz's love gurus. MELISSA RAUCH reprises her role as Howard's girlfriend, Bernadette.
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Episode 68

Season 4, Episode 5: The Desperation Emanation (2010)
20 min
Leonard realizes he's the only one without a girlfriend, while Sheldon wants to get rid of his.
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Episode 69

Season 4, Episode 6: The Irish Pub Formulation (2010)
21 min
A visit from Raj's sister (guest star AARTI MANKAD) creates tension among the guys – especially when Leonard keeps an affair secret from Sheldon, Howard and Raj.
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Episode 70

Season 4, Episode 7: The Apology Insufficiency (2010)
21 min
When an FBI agent (guest star ELIZA DUSHKU) interviews the guys for Wolowitz's security clearance, Sheldon's answers during the screening, put Wolowitz's clearance in jeopardy.
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Episode 71

Season 4, Episode 8: The 21-Second Excitation (2010)
19 min
When the guys camp in line for a screening, their plans are thwarted by Sheldon's greatest nemesis, WIL WHEATON (guest starring as himself). Meanwhile, Penny and Bernadette invite Amy to her first slumber party.
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Episode 72

Season 4, Episode 9: The Boyfriend Complexity (2010)
21 min
Penny asks Leonard to lie to her father, Wyatt (guest star KEITH CARRADINE), while Howard, Raj and Bernadette pull an all-nighter at a telescope.
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Episode 73

Season 4, Episode 10: The Alien Parasite Hypothesis (2011)
20 min
Amy finds she has sexual feelings for Penny's ex, Zack (guest star BRIAN THOMAS SMITH) while Koothrappali and Wolowitz try to prove who would be the better superhero.
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Episode 74

Season 4, Episode 11: The Justice League Recombination (2011)
20 min
The guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.
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Episode 75

Season 4, Episode 12: The Bus Pants Utilization (2011)
21 min
Leonard's idea for a smartphone app derails his friendship with Sheldon as they fight for control of the project.
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Episode 76

Season 4, Episode 13: The Love Car Displacement (2011)
21 min
Tension runs high when everyone is staying at the same hotel for a science event and Bernadette runs into her ex-boyfriend (guest star RICK FOX, three-time NBA champion with the Los Angeles Lakers).
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Episode 77

Season 4, Episode 14: The Thespian Catalyst (2011)
21 min
Sheldon wants Penny to give him acting lessons, hoping that they will help him become a better teacher. Meanwhile, Koothrappali fantasizes about his best friend's girlfriend.
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Episode 78

Season 4, Episode 15: The Benefactor Factor (2011)
20 min
A wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science. JESSICA WALTER (Arrested Development) guest stars as the widowed benefactress and JOSHUA MALINA (The West Wing) guest stars as the University President.
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Episode 79

Season 4, Episode 16: The Cohabitation Formulation (2011)
20 min
As Wolowitz contemplates taking things with Bernadette to the next level, he must choose between his girlfriend and his mother. Meanwhile, Leonard rekindles his relationship with Raj's sister, Priya.
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Episode 80

Season 4, Episode 17: The Toast Derivation (2011)
21 min
When the gang starts hanging out at Raj's and Sheldon realizes it's actually Leonard who is the center of their social group, Sheldon decides to get a new group of friends.
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Episode 81

Season 4, Episode 18: The Prestidigitation Approximation (2011)
21 min
Leonard must choose between his new girlfriend, Priya, and his friendship with Penny. Meanwhile, Howard drives Sheldon crazy with a magic trick.
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Episode 82

Season 4: Episode 19: The Zarnecki Incursion (2011)
21 min
When someone hacks Sheldon's online gaming account, the guys go on a quest to find the culprit.
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Episode 83

Season 4, Episode 20: The Herb Garden Germination (2011)
21 min
Sheldon and Amy experiment on their friends by spreading gossip, while Howard takes a big step in his relationship with Bernadette.
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Episode 84

Season 4, Episode 21: The Agreement Dissection (2011)
20 min
Priya uses her lawyer skills to pick apart the roommate agreement…and put Sheldon in his place. Meanwhile, the girls take Sheldon dancing.
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Episode 85

Season 4, Episode 22: The Wildebeest Implementation (2011)
21 min
Raj attempts to cure his social anxiety disorder of talking to women, while Penny uses Bernadette to spy on Leonard and his girlfriend.
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Episode 86

Season 4, Episode 23: The Engagement Reaction (2011)
19 min
When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.
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Episode 87

Season 4, Episode 24: The Roomate Transmorgrification (2011)
21 min
When Bernadette receives her Ph.D., the guys take joy in reminding an emasculated Wolowitz that he is the only one in their group who isn't a doctor. Meanwhile, Koothrappali becomes Sheldon's new roommate after hearing Leonard and Priya engaging in a Star Trek bedroom fantasy, on the fourth season finale.
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Episode 88

Season 5, Episode 1: The Skank Reflex Analysis (2011)
21 min
The fifth season premiere picks up where the fourth season finale left off as the gang deals with the aftermath of Penny and Raj's night together. While Penny worries that she's screwed things up permanently with her friends, Sheldon takes command of the paintball team. Emmy® nominee CHRISTINE BARANSKI (The Good Wife) reprises her role as Leonard's emotionally distant mother.
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Episode 89

Season 5, Episode 2: The Infestation Hypothesis (2011)
19 min
A battle of wills between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya (recurring guest star AARTI MANN), who has moved back to India.
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Episode 90

Season 5, Episode 3: The Pulled Groin Extrapolation (2011)
20 min
Leonard attends a co-worker's wedding as Amy's date. Meanwhile, Howard tries to convince Bernadette to live with his mom after they get married by suggesting a trial run with the two of them staying with his mom over the weekend.
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Episode 91

Season 5, Episode 4: The Wiggly Finger Catalyst (2011)
20 min
When Raj is upset he's the only one of the four guys who is not in a relationship, Penny sets out to find the perfect date, introducing him to Emily (guest star KATIE LeCLERC – Switched at Birth) a girl he can actually talk to!
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Episode 92

Season 5, Episode 5: The Russian Rocket Reaction (2011)
21 min
Sheldon's old nemesis, WIL WHEATON (guest starring as Himself), returns and invites everyone to a housewarming party. Sheldon threatens to "defriend" Leonard if he attends. But when he hears that BRENT SPINER (guest starring as Himself), the actor who played Commander Data, will be there, Sheldon decides to go to the party after all… only to discover new levels of treachery. Meanwhile, Howard gets an out-of-this-world opportunity that Bernadette reacts to strongly.
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Episode 93

Season 5, Episode 6: The Rhinitis Revelation (2011)
21 min
Craving a little motherly love, Sheldon competes with the gang for his mother's attention when she comes to visit. LAURIE METCALF reprises her role as Sheldon's mother, Mary.
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Episode 94

Season 5, Episode 7: The Good Guy Fluctuation (2011)
19 min
A cute comic book artist (guest star COURTNEY FORD) puts Leonard's relationship with Priya to the test; while Sheldon, getting into the spirit of Halloween, tries to scare the guys.
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Episode 95

Season 5, Episode 8: The Isolation Permutation (2011)
21 min
Amy is heartbroken when Bernadette and Penny go shopping for wedding dresses without her.
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Episode 96

Season 5, Episode 9: The Ornithophobia Diffusion (2011)
21 min
Can friends with benefits still be friends without? Leonard and Penny try hanging out alone, while Sheldon must overcome his fear of birds.
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Episode 97

Season 5, Episode 10: The Flaming Spittoon Acquisition (2011)
20 min
Sheldon becomes jealous and considers taking his relationship with Amy to the next level when Stuart (guest star KEVIN SUSSMAN) from the comic book store asks her out on a date.
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Episode 98

Season 5, Episode 11: The Speckerman Recurrence (2011)
19 min
Leonard must face his fears after being contacted by his high school tormentor (guest star LANCE BARBER), while Penny realizes that she might have been a bully herself.
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Episode 99

Season 5, Episode 12: The Shiny Trinket Maneuver (2012)
20 min
Sheldon gets in trouble with Amy when he isn't impressed by her recent accomplishment, and it's up to Penny to teach him how to be a better boyfriend. Howard, meanwhile, must come to grips with Bernadette's dislike of children.
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Episode 100

Season 5, Episode 13: The Recombination Hypothesis (2012)
21 min
The possibility of Leonard and Penny getting back together could prove disastrous when Leonard offers Penny a spur of the moment invitation to a romantic dinner for two on the 100th episode of the series.
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Episode 101

Season 5, Episode 14: The Beta Test Initiation (2012)
20 min
Leonard and Penny experiment with dating again by "beta testing" their relationship, while Raj develops a peculiar relationship with his phone's virtual assistant.
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Episode 102

Season 5, Episode 15: The Friendship Contraction (2012)
20 min
Sheldon's selfish demands force Leonard to reconsider their friendship. Could this be the end of The Roommate Agreement? Meanwhile, Howard tries to pick his astronaut nickname, but NASA astronaut MIKE MASSIMINO (guest starring as himself) has other ideas.
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Episode 103

Season 5, Episode 16: The Vacation Solution (2012)
21 min
When Sheldon is forced to take a vacation by the university, he goes to work with Amy in her neurobiology lab. Meanwhile, Bernadette wants Howard to sign a pre-nuptial agreement.
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Episode 104

Season 5, Episode 17: The Rothman Disintegration (2012)
21 min
When a corner office at the University opens up, Sheldon must compete for it with his office nemesis, Barry Kripke. Meanwhile, a personal gift from Amy makes Penny uncomfortable.
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Episode 105

Season 5, Episode 18: The Werewolf Transformation (2012)
21 min
Sheldon's life is turned upside-down after his barber becomes hospitalized. Now, that there's been a change in his routine, Sheldon finds himself re-evaluating his entire life. Meanwhile, astronaut training causes Howard to rethink his decision to go into space.
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Episode 106

Season 5, Episode 19: The Weekend Vortex (2012)
20 min
It's on…like Alderaan, when the guys plan a weekend Star Wars gaming marathon! But when Sheldon chooses the guys-only weekend over a weekend with Amy to visit her aunt, he is destined to feel the force!
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Episode 107

Season 5, Episode 20: The Transporter Malfunction (2012)
21 min
It's a dream come true for Sheldon when he has a close encounter with his hero, Mr. Spock. Legendary sci-fi icon LEONARD NIMOY guest stars, lending his voice to a unique reprisal of his three-time Emmy®-nominated Star Trek role.
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Episode 108

Season 5, Episode 21: The Hawking Excitation (2012)
19 min
When Wolowitz gets tow work with world-renowned scientist STEPHEN HAWKING (guest starring as Himself), Sheldon is willing to do anything to meet his hero.
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Episode 109

Season 5, Episode 22: The Stag Convergence (2012)
21 min
Howard's wedding plans are in jeopardy after the guys (and Wil Wheaton) throw him a bachelor party. After details of his sexual history are leaked online, Bernadette reconsiders marrying Howard.
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Episode 110

Season 5, Episode 23: The Launch Acceleration (2012)
21 min
When NASA reschedules Howard's mission and puts his wedding plans in jeopardy, he's forced to face his fears and Bernadette's dad (guest star CASEY SANDER). Meanwhile, Leonard says something surprising to Penny in the bedroom.
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Episode 111

Season 5, Episode 24: The Countdown Reflection (2012)
21 min
Howard Wolowitz crosses over into the final frontiers of space…and marriage on the fifth season finale. When Howard and Bernadette decide they want to be married before his NASA space launch, the gang rushes to put on a wedding. NASA Astronaut Mike Massimino guest stars as Himself.
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Episode 112

Season 6, Episode 1: The Date Night Variable (2012)
21 min
On the sixth season premiere, Howard discovers that he can't escape his mother – even in space! Caught in an argument between Bernadette and his mom (recurring guest voice CAROL ANN SUSI), Howard deals with woman trouble from the International Space Station. Back on earth, meanwhile, Raj faces his loneliness, by turning his existence as a third wheel into an art form.
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Episode 113

Season 6, Episode 2: The Decoupling Fluctuation (2012)
21 min
When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. But Sheldon is no good at keeping secrets. Meanwhile, Howard is being picked on in space by the other astronauts (guest stars PASHA LYCHNIKOFF and MIKE MASSIMINO).
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Episode 114

Season 6, Episode 3: The Higgs Boson Observation (2012)
19 min
While the pressures of being in space starts to take its toll on Howard, Amy feels threatened when Sheldon hires a young female assistant, Alex (guest star MARGO HARSHMAN).
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Episode 115

Season 6, Episode 4: The Re-Entry Minimization (2012)
20 min
When Howard returns from space, he doesn't get the hero's welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.
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Episode 116

Season 6, Episdoe 5: The Holographic Excitation (2012)
21 min
The gang celebrates Halloween at Stuart's comic book store. Meanwhile Leonard and Penny discover a new spark in their relationship when he seduces her with science. And while Howard can't stop talking about space, it takes iconic astronaut BUZZ ALDRIN (guest starring as himself) to get him grounded again.
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Episode 117

Season 6, Episode 6: The Extract Obilteration (2012)
21 min
Sheldon's tenuous relationship with renowned scientist STEPHEN HAWKING is threatened by a game of "Words with Friends," while Penny secretly enrolls in a class at the local college.
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Episode 118

Season 6, Episode 7: The Habitation Configuration (2012)
21 min
Pressured by Bernadette, Howard comes to terms with moving out of his mother's house. Meanwhile, Sheldon, who's caught in the middle of a feud between his "girlfriend" Amy and good friend WIL WHEATON, goes to Penny for advice. Star Trek's LeVAR BURTON guest stars.
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Episode 119

Season 6, Episode 8: The 43 Peculiarity (2013)
21 min
Howard and Raj try to get to the bottom of why Sheldon disappears every afternoon at 2:45. Meanwhile, Leonard and Penny wrestle with jealousy in their relationship.
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Episode 120

Season 6, Episode 9: The Parking Spot Escalation (2013)
19 min
When the University reassigns Sheldon's (unused) parking spot to Howard, the ensuing turf battle affects the whole gang.
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Episode 121

Season 6, Episode 10: The Fish Guts Displacement (2013)
21 min
Sheldon plays nursemaid to a sick Amy, while Howard attempts to bond with his father-in-law (guest star CASEY SANDER) on an upcoming fishing trip.
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Episode 122

Season 6, Episode 11: The Santa Simulation (2013)
21 min
Sheldon unwillingly revisits some Christmas memories during a lively game of Dungeons and Dragons, while Penny, Bernadette and Amy try to find the perfect girl for Raj when he joins the girls for ladies night.
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Episode 123

Season 6, Episode 12: The Egg Salad Equivalency (2013)
21 min
Sheldon is accused of sexual harassment at the University and winds up dragging Leonard, Raj and Howard into the fray. Southland's REGINA KING guest stars as the University's Director of Employee Relations.
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Episode 124

Season 6, Episode 13: The Bakersfield Expedition (2013)
21 min
While the guys take a road trip to a comic book convention in Bakersfield dressed as characters from Star Trek: The Next Generation, Leonard's car is stolen. Meanwhile, the girls stay home and try to appreciate the world of comics.
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Episode 125

Season 6, Episode 14: The Cooper/Kripke Inversion (2013)
19 min
Outraged that he's being forced to work with his university nemesis, Barry Kripke (guest star JOHN ROSS BOWIE), Sheldon faces a crisis of conscience. Meanwhile, Howard and Raj spend a thousand dollars on action figures of themselves.
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Episode 126

Season 6, Episode 15: The Spoil Alert Segmentation (2013)
20 min
A fight between Leonard and Sheldon drives Leonard to finally move in with Penny – not realizing how the shift will affect Penny and Amy's living arrangements. Meanwhile, Raj takes care of Mrs. Wolowitz while Howard is away.
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Episode 127

Season 6, Episode 16: The Tangible Affection Proof (2013)
20 min
While the guys try to give their significant others the perfect Valentine's Day, Raj and Stuart throw a lonely people party at the comic book store.
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Episode 128

Season 6, Episode 17: The Monster Isolation (2013)
20 min
After a terrible date, Raj vows to never leave his apartment again. Meanwhile, Penny actually impresses Sheldon with her acting skills.
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Episode 129

Season 6, Episode 18: The Contractual Obligation Implementation (2013)
20 min
Back to school! Leonard, Sheldon and Howard try to advance the cause of women in science by speaking with junior high girls about their future careers, while Raj plans his date with Lucy (guest star KATE MICUCCI).
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Episode 130

Season 6, Episode 19: The Closet Reconfiguration (2013)
19 min
When Howard finds a letter from his father, he's forced to confront his past, struggling with whether or not he should open it. And Leonard and Penny throw a "grown-up" cocktail party at the apartment.
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Episode 131

Season 6, Episode 20: The Tenure Turbulence (2013)
19 min
Let the battle begin! Leonard, Sheldon and Raj fight for tenure at the University – and the competition heats up when the girls get involved!
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Episode 132

Season 6, Episode 21: The Closure Alternative (2013)
19 min
Sheldon feels lost after one of his favorite TV shows gets canceled too soon, so Amy tries to help him get over his compulsive need for closure. Meanwhile, Raj discovers a secret about his new love interest, Lucy.
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Episode 133

Season 6, Episode 22: The Proton Resurgence (2013)
21 min
Sheldon and Leonard hire Professor Proton (guest star BOB NEWHART), the host of their favorite childhood TV show, to perform. Also, Howard and Bernadette run into trouble babysitting Raj's dog.
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Episode 134

Season 6, Episode 23: The Love Spell Potential (2013)
20 min
When the girls' trip to Vegas falls through, the guys invite them to play Dungeons & Dragons – causing Sheldon and Amy's relationship to take an unexpected turn. Meanwhile, Raj and Lucy go on a very awkward date.
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Episode 135

Season 6, Episode 24: The Bon Voyage Reaction (2013)
19 min
When Leonard is offered an exciting new job opportunity overseas, Sheldon grows very jealous and Penny is thrown for a loop. Meanwhile, Raj pushes Lucy a little too far in their relationship on the sixth season finale.
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Summary

Episode 1

Episode 2

Episode 3

Episode 4

Episode 5

Episode 6

Episode 7

Episode 8

Episode 9

Episode 10

Episode 11

Episode 12

Episode 13

Episode 14

Episode 15

Episode 16

Episode 17

Summary

Episode 1

Episode 2

Episode 3

Episode 4

Episode 5

Episode 6

Episode 7

Episode 8

Episode 9

Episode 10

Episode 11

Episode 12

Episode 13

Episode 14

Episode 15

Episode 16

Episode 17

Episode 18

Episode 19

Episode 20

Episode 21

Episode 22

Episode 23

Episode 24

Episode 25

Episode 26

Episode 27

Episode 28

Episode 29

Episode 30

Episode 31

Episode 32

Episode 33

Episode 34

Episode 35

Episode 36

Episode 37

Episode 38

Episode 39

Episode 40

Episode 41

Episode 42

Episode 43

Episode 44

Episode 45

Episode 46

Episode 47

Episode 48

Episode 49

Episode 50

Episode 51

Episode 52

Episode 53

Episode 54

Episode 55

Episode 56

Episode 57

Episode 58

Episode 59

Episode 60

Episode 61