Sept. 22, 2008, midnight 7.8
S2E1 - The Bad Fish Paradigm
Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.
Sept. 29, 2008, midnight 7.6
S2E2 - The Codpiece Topology
A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.
Oct. 6, 2008, midnight 7.8
S2E3 - The Barbarian Sublimation
Sheldon creates a monster when he introduces Penny to online gaming.
Oct. 13, 2008, midnight 7.5
S2E4 - The Griffin Equivalency
Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.
Oct. 20, 2008, midnight 7.5
S2E5 - The Euclid Alternative
Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.
Nov. 3, 2008, midnight 7.8
S2E6 - The Cooper-Nowitzki Theorem
Sheldon and the gang are confused when a young grad student is attracted to him.
Nov. 10, 2008, midnight 7.9
S2E7 - The Panty Piñata Polarization
When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.
Nov. 17, 2008, midnight 7.4
S2E8 - The Lizard-Spock Expansion
Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.
Nov. 24, 2008, midnight 7.4
S2E9 - The White Asparagus Triangulation
Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.
Dec. 8, 2008, midnight 7.0
S2E10 - The Vartabedian Conundrum
Leonard asks Penny for advice when his new relationship starts moving too fast.
Dec. 15, 2008, midnight 8.2
S2E11 - 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.
Jan. 12, 2009, midnight 7.4
S2E12 - 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.
Jan. 19, 2009, midnight 7.4
S2E13 - The Friendship Algorithm
Sheldon creates a scientific procedure for making friends.
Feb. 2, 2009, midnight 7.4
S2E14 - The Financial Permeability
Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.
Feb. 9, 2009, midnight 8.2
S2E15 - The Maternal Capacitance
Leonard and Penny are drawn together after a disastrous visit from Leonard's mother.
March 2, 2009, midnight 7.4
S2E16 - The Cushion Saturation
A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.
March 9, 2009, midnight 7.5
S2E17 - 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 16, 2009, midnight 7.5
S2E18 - The Work Song Nanocluster
Penny's home business turns into a complete nightmare when Sheldon takes over.
March 30, 2009, midnight 7.5
S2E19 - The Dead Hooker Juxtaposition
Penny squares off with a new beautiful female neighbor who may become the building's "new Penny."
April 13, 2009, midnight 7.6
S2E20 - 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 27, 2009, midnight 7.5
S2E21 - 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.
May 4, 2009, midnight 7.5
S2E22 - 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 11, 2009, midnight 7.5
S2E23 - The Monopolar Expedition
The guys' plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.
