The Big Bang Theory Season 2 Episode release dates & where to watch

1. The Bad Fish Paradigm

Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.

2. The Codpiece Topology

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

3. The Barbarian Sublimation

Sheldon creates a monster when he introduces Penny to online gaming.

4. The Griffin Equivalency

Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.

5. The Euclid Alternative

Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.

6. The Cooper-Nowitzki Theorem

Sheldon and the gang are confused when a young grad student is attracted to him.

7. The Panty Piñata Polarization

When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.

8. The Lizard-Spock Expansion

Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.

9. The White Asparagus Triangulation

Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.

10. The Vartabedian Conundrum

Leonard asks Penny for advice when his new relationship starts moving too fast.

11. The Bath Item Gift Hypothesis Mid-season finale

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

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

Sheldon creates a scientific procedure for making friends.

14. The Financial Permeability

Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.

15. The Maternal Capacitance

Leonard and Penny are drawn together after a disastrous visit from Leonard's mother.

16. The Cushion Saturation

A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.

17. 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.

18. The Work Song Nanocluster

Penny's home business turns into a complete nightmare when Sheldon takes over.

19. The Dead Hooker Juxtaposition

Penny squares off with a new beautiful female neighbor who may become the building's "new Penny."

20. The Hofstadter Isotope

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

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

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 Finale

The guys' plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.