Season 2

I’m not interested in caring about people. – Ron Swanson

Preview
18
S02E01
The Bad Fish Paradigm
Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.
September 22, 2008
19
S02E02
The Codpiece Topology
A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.
September 29, 2008
20
S02E03
The Barbarian Sublimation
Sheldon creates a monster when he introduces Penny to online gaming.
October 6, 2008
21
S02E04
The Griffin Equivalency
Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.
October 13, 2008
22
S02E05
The Euclid Alternative
Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.
October 20, 2008
23
S02E06
The Cooper-Nowitzki Theorem
Sheldon and the gang are confused when a young grad student is attracted to him.
November 3, 2008
24
S02E07
The Panty Piñata Polarization
When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.
November 10, 2008
25
S02E08
The Lizard-Spock Expansion
Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.
November 17, 2008
26
S02E09
The White Asparagus Triangulation
Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.
November 24, 2008
27
S02E10
The Vartabedian Conundrum
Leonard asks Penny for advice when his new relationship starts moving too fast.
December 8, 2008
28
S02E11
The Bath Item Gift Hypothesis
Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.
December 15, 2008
29
S02E12
The Killer Robot Instability
Penny's criticism of Wolowitz's romantic life pushes him into depression and AWOL for a fighting robot battle the rest of guys are depending on him for.
January 12, 2009
30
S02E13
The Friendship Algorithm
Sheldon creates a scientific procedure for making friends.
January 19, 2009
31
S02E14
The Financial Permeability
Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.
February 2, 2009
32
S02E15
The Maternal Capacitance
Leonard and Penny are drawn together after a disastrous visit from Leonard's mother.
February 9, 2009
33
S02E16
The Cushion Saturation
A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.
March 2, 2009
34
S02E17
The Terminator Decoupling
Leonard, Sheldon and Wolowitz are ecstatic to learn that a famous science-fiction actress (Summer Glau) is on board the train they are taking to San Francisco.
March 9, 2009
35
S02E18
The Work Song Nanocluster
Penny's home business turns into a complete nightmare when Sheldon takes over.
March 16, 2009
36
S02E19
The Dead Hooker Juxtaposition
Penny squares off with a new beautiful female neighbor who may become the building's "new Penny."
March 30, 2009
37
S02E20
The Hofstadter Isotope
A fellow comic book enthusiast's hitting on Penny leads to Leonard and Howard going to a bar's Ladies' Night.
April 13, 2009
38
S02E21
The Vegas Renormalization
Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas, and Sheldon becomes locked out of his apartment and must stay with Penny.
April 27, 2009
39
S02E22
The Classified Materials Turbulence
Penny's second date with Stuart sees her making a comment that gives Leonard new hope for a relationship with her. Wolowitz realizes there's a crucial error in a NASA project he's working on.
May 4, 2009
40
S02E23
The Monopolar Expedition
The guys' plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.
May 11, 2009