Season 2
23 episodes
1. The Bad Fish Paradigm
22m · Sep 22, 2008
Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.
2. The Codpiece Topology
21m · Sep 29, 2008
A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.
3. The Barbarian Sublimation
21m · Oct 6, 2008
Sheldon creates a monster when he introduces Penny to online gaming.
4. The Griffin Equivalency
21m · Oct 13, 2008
Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.
5. The Euclid Alternative
20m · Oct 20, 2008
Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.
6. The Cooper-Nowitzki Theorem
21m · Nov 3, 2008
Sheldon and the gang are confused when a young grad student is attracted to him.
7. The Panty Piñata Polarization
21m · Nov 10, 2008
When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.
8. The Lizard-Spock Expansion
20m · Nov 17, 2008
Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.
9. The White Asparagus Triangulation
21m · Nov 24, 2008
Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.
10. The Vartabedian Conundrum
21m · Dec 8, 2008
Leonard asks Penny for advice when his new relationship starts moving too fast.
11. The Bath Item Gift Hypothesis
21m · Dec 15, 2008
Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.
12. The Killer Robot Instability
21m · Jan 12, 2009
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.
13. The Friendship Algorithm
21m · Jan 19, 2009
Sheldon creates a scientific procedure for making friends.
14. The Financial Permeability
21m · Feb 2, 2009
Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.
15. The Maternal Capacitance
21m · Feb 9, 2009
Leonard and Penny are drawn together after a disastrous visit from Leonard's mother.
16. The Cushion Saturation
21m · Mar 2, 2009
A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.
17. The Terminator Decoupling
21m · Mar 9, 2009
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.
18. The Work Song Nanocluster
20m · Mar 16, 2009
Penny's home business turns into a complete nightmare when Sheldon takes over.
19. The Dead Hooker Juxtaposition
20m · Mar 30, 2009
Penny squares off with a new beautiful female neighbor who may become the building's "new Penny."
20. The Hofstadter Isotope
20m · Apr 13, 2009
A fellow comic book enthusiast's hitting on Penny leads to Leonard and Howard going to a bar's Ladies' Night.
21. The Vegas Renormalization
22m · Apr 27, 2009
Leonard and Koothrappali escort a heartbroken Wolowitz to Las Vegas, and Sheldon becomes locked out of his apartment and must stay with Penny.
22. The Classified Materials Turbulence
19m · May 4, 2009
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.
23. The Monopolar Expedition
21m · May 11, 2009
The guys' plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.