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The Big Bang Theory Season 2 Episodes

23 Episodes 2008 - 2009

The second season begins with Leonard (Johnny Galecki) and Penny (Kaley Cuoco) returning from their first date, but things don't work out exactly as planned. Meanwhile, despite becoming even more obsessive and neurotic, Sheldon (Jim Parsons) strikes up an unusual friendship with Penny. Sara Gilbert has a recurring character arc as a fellow scientist who's interested in Leonard; and memorable guest cameos include Charlie Sheen, Summer Glau and George Smoot. Simon Helberg and Kunal Nayyar also star.

Episode 1

The Bad Fish Paradigm

Mon, Sep 22, 2008 30 mins

In the second-season opener, Penny surprisingly turns to Sheldon as a confidant after her disastrous first date with Leonard.

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Episode 2

The Codpiece Topology

Mon, Sep 29, 2008 30 mins

A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.

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Episode 3

The Barbarian Sublimation

Mon, Oct 6, 2008 30 mins

Sheldon shows Penny the joys of online gaming, creating an addict in the process.

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Episode 4

The Griffin Equivalency

Mon, Oct 13, 2008 30 mins

Raj gets an ego boost after winning some fame from a magazine article and risks his friendship with Leonard by trying to win over Penny.

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Episode 5

The Euclid Alternative

Mon, Oct 20, 2008 30 mins

The friends band together to help Sheldon face his fear of driving.

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Episode 6

The Cooper-Nowitzki Theorem

Mon, Nov 3, 2008 30 mins

The gang is puzzled by a young graduate student's attraction to Sheldon.

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Episode 7

The Panty Piñata Polarization

Mon, Nov 10, 2008 30 mins

It's an all-out war between Penny and Sheldon when he bans her from the apartment for what she thinks are petty infractions.

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Episode 8

The Lizard-Spock Expansion

Mon, Nov 17, 2008 30 mins

A smitten Wolowitz thinks he's found his soul mate, until the woman meets Leonard.

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Episode 9

The White Asparagus Triangulation

Mon, Nov 24, 2008 30 mins

Sheldon is ecstatic when Leonard begins dating Stephanie, who meets all of Sheldon's seemingly impossible standards.

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Episode 10

The Vartabedian Conundrum

Mon, Dec 8, 2008 30 mins

Leonard's relationship with Stephanie is moving too fast for him, so he runs to Penny for advice.

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Episode 11

The Bath Item Gift Hypothesis

Mon, Dec 15, 2008 30 mins

Christmas brings no tidings of comfort and joy to Leonard, whose colleague starts dating Penny. Meanwhile, Sheldon drives everyone crazy over his adherence to gift-giving etiquette.

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Episode 12

The Killer Robot Instability

Mon, Jan 12, 2009 30 mins

Penny wounds Wolowitz with a comment about his love life, prompting him to abandon friends who need him for a fighting-robot contest.

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Episode 13

The Friendship Algorithm

Mon, Jan 19, 2009 30 mins

Here's a conundrum to baffle the guys: Sheldon's intelligence, which renders him socially awkward, is also the source of his new scientific procedure for making friends.

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Episode 14

The Financial Permeability

Mon, Feb 2, 2009 30 mins

Sheldon helps Penny with a financial crisis, but his solution leads to a confrontation between Leonard and Penny's burly ex-boyfriend Kurt.

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Episode 15

The Maternal Capacitance

Mon, Feb 9, 2009 30 mins

Leonard suffers through a dreadful visit from his mother that ends up bringing him and Penny closer.

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Episode 16

The Cushion Saturation

Mon, Mar 2, 2009 30 mins

A paintball game has Penny and Sheldon engaging in their own personal battle and Leslie and Wolowitz finding romance.

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Episode 17

The Terminator Decoupling

Mon, Mar 9, 2009 30 mins

The guys' trip to San Francisco takes a detour once they learn that actress Summer Glau is on their train.

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Episode 18

The Work Song Nanocluster

Mon, Mar 16, 2009 30 mins

Penny starts a hair-product business that suffers when her friends, particularly Sheldon, become involved.

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Episode 19

The Dead Hooker Juxtaposition

Mon, Mar 30, 2009 30 mins

Penny develops a rivalry with a pretty woman who moves into the building.

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Episode 20

The Hofstadter Isotope

Mon, Apr 13, 2009 30 mins

Penny is romanced by a friend of the guys' while at a comic-book store. Meanwhile, Leonard and Wolowitz search for love at a bar's ladies' night.

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Episode 21

The Vegas Renormalization

Mon, Apr 27, 2009 30 mins

Leonard, Koothrappali and Wolowitz go to Las Vegas, and Sheldon is locked out of the apartment, leaving him no choice but to stay with Penny.

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Episode 22

The Classified Materials Turbulence

Mon, May 4, 2009 30 mins

While on a date with Stuart, Penny makes an unexpected discovery regarding Leonard; and Wolowitz asks for his friends' help on his NASA project when he uncovers a design flaw.

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Episode 23

The Monopolar Expedition

Mon, May 11, 2009 30 mins

In the second-season finale, Leonard gets ready for a three-month long science trip, and he and Penny come to terms with their feelings for each other.

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