The Big Bang Theory · Season 2
23 episodes listed, beginning 2008-09-22.
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- Episode 1
The Bad Fish Paradigm
30 minutes
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After her first date with Leonard goes awry, Penny finds an unwilling confidant in Leonard's anti-social roommate, Sheldon.
- Episode 2
The Codpiece Topology
30 minutes
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When Leonard sees Penny with a handsome new guy, he enters into a rebound relationship with Sheldon's nemesis, Leslie Winkle.
- Episode 3
The Barbarian Sublimation
30 minutes
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Sheldon creates a monster when he introduces Penny to the world of online gaming.
- Episode 4
The Griffin Equivalency
30 minutes
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Raj, newly famous because of an article in a magazine, gets a big head and makes a disastrous play for Leonard's crush, Penny.
- Episode 5
The Euclid Alternative
30 minutes
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Leonard and his friends stage an intervention to make Sheldon confront his longstanding refusal to drive.
- Episode 6
The Cooper-Nowitzki Theorem
30 minutes
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Young grad student's attraction to Sheldon confuses everyone, including Sheldon himself.
- Episode 7
The Panty Piñata Polarization
30 minutes
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Penny vows to get revenge on Sheldon when he bans her from the apartment for a series of petty infractions.
- Episode 8
The Lizard-Spock Expansion
30 minutes
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Wolowitz thinks he's found the love of his life, until she meets Leonard.
- Episode 9
The White Asparagus Triangulation
30 minutes
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Sheldon can barely contain his joy when Leonard starts dating a woman who meets Sheldon's exacting standards.
- Episode 10
The Vartabedian Conundrum
30 minutes
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Sheldon uses Dr. Stephanie to check all his hypochondriac symptoms. When Leonard's relationship with a new woman starts moving too fast for him, he goes to Penny for advice.
- Episode 11
The Bath Item Gift Hypothesis
30 minutes
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Christmas is a source of stress for Leonard - whose handsome colleague starts dating Penny - and his friends, who are being tormented by Sheldon's obsession with gift-giving etiquette.
- Episode 12
The Killer Robot Instability
30 minutes
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When Penny's comment about Wolowitz's love life sends him into a depressed stupor, his friends lose their most important team-mate in an upcoming fighting robot competition.
- Episode 13
The Friendship Algorithm
30 minutes
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Socially awkward Sheldon develops a scientific procedure for making friends.
- Episode 14
The Financial Permeability
30 minutes
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Sheldon's "simple" solution to Penny's financial problem leads to a confrontation between Leonard and Penny's hulking ex-boyfriend, Kurt.
- Episode 15
The Maternal Capacitance
30 minutes
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Disastrous visit from Mrs. Hofstadter brings Leonard and Penny closer together.
- Episode 16
The Cushion Saturation
30 minutes
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Paintball game leads to a fight between Penny and Sheldon, and romance for Wolowitz and Leslie.
- Episode 17
The Terminator Decoupling
30 minutes
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Train trip to San Francisco takes a major detour when Sheldon discovers he forgot his flash drive and Leonard, Wolowitz and Raj discover that sci-fi actor Summer Glau is onboard.
- Episode 18
The Work Song Nanocluster
30 minutes
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Penny's home hair products business becomes a complete nightmare when a caffeine-addled Sheldon takes over.
- Episode 19
The Dead Hooker Juxtaposition
30 minutes
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Penny develops a rivalry with a sexy female neighbor who threatens to become "The New Penny" in the building.
- Episode 20
The Hofstadter Isotope
30 minutes
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While 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.
- Episode 21
The Vegas Renormalization
30 minutes
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Leonard and Koothrappali take a heartbroken Wolowitz to Las Vegas, leaving Sheldon locked out of his apartment and forced to bunk with Penny.
- Episode 22
The Classified Materials Turbulence
30 minutes
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Things begin to look up for Leonard when Penny makes a surprising revelation on her second date with Stuart. Meanwhile, Wolowitz enlists his friends' help when he discovers a critical design flaw in his project for NASA.
- Episode 23
The Monopolar Expedition
30 minutes
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Penny is conflicted when Leonard and his friends decide to spend the summer working - at the North Pole.
Original air-order information: TVmaze, CC BY-SA 4.0. Listed through September 10, 2026. Regular episodes only; specials and future air dates are not included.