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.
Released: 10/13/2008
Directors:
Mark Cendrowski5. The Euclid Alternative
Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.
Released: 10/20/2008
Directors:
Mark Cendrowski6. The Cooper-Nowitzki Theorem
Sheldon and the gang are confused when a young grad student is attracted to him.
Released: 11/3/2008
Directors:
Mark Cendrowski7. The Panty Piñata Polarization
When Sheldon bans Penny from the apartment for numerous minor infractions, she decides to retaliate.
Released: 11/10/2008
Directors:
Mark Cendrowski8. 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.
Released: 11/24/2008
Directors:
Mark Cendrowski10. The Vartabedian Conundrum
Leonard asks Penny for advice when his new relationship starts moving too fast.
Released: 12/8/2008
Directors:
Mark Cendrowski11. 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.
Released: 12/15/2008
Directors:
Mark Cendrowski12. 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.
Released: 1/12/2009
Directors:
Mark Cendrowski13. The Friendship Algorithm
Sheldon creates a scientific procedure for making friends.
Released: 1/19/2009
Directors:
Mark Cendrowski14. The Financial Permeability
Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.
Released: 2/2/2009
Directors:
Mark Cendrowski15. The Maternal Capacitance
Leonard and Penny are drawn together after a disastrous visit from Leonard's mother.
Released: 2/9/2009
Directors:
Mark Cendrowski16. 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.
Released: 3/9/2009
Directors:
Mark Cendrowski18. The Work Song Nanocluster
Penny's home business turns into a complete nightmare when Sheldon takes over.
Released: 3/16/2009
Directors:
Peter Chakos19. 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.
Released: 4/27/2009
Directors:
Mark Cendrowski22. 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.
Released: 5/4/2009
Directors:
Mark Cendrowski23. The Monopolar Expedition
The guys' plan to work over the summer at the North Pole makes Penny revaluate her feelings for Leonard.