E1 - The Bad Fish Paradigm

Aired: September 22, 2008

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

E2 - The Codpiece Topology

Aired: September 29, 2008

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

E3 - The Barbarian Sublimation

Aired: October 06, 2008

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

E4 - The Griffin Equivalency

Aired: October 13, 2008

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

E5 - The Euclid Alternative

Aired: October 20, 2008

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

E6 - The Cooper-Nowitzki Theorem

Aired: November 03, 2008

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

E7 - The Panty Piñata Polarization

Aired: November 10, 2008

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

E8 - The Lizard-Spock Expansion

Aired: November 17, 2008

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

E9 - The White Asparagus Triangulation

Aired: November 24, 2008

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

E10 - The Vartabedian Conundrum

Aired: December 08, 2008

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

E11 - The Bath Item Gift Hypothesis

Aired: December 15, 2008

Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.

E12 - The Killer Robot Instability

Aired: January 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.

E13 - The Friendship Algorithm

Aired: January 19, 2009

Sheldon creates a scientific procedure for making friends.

E14 - The Financial Permeability

Aired: February 02, 2009

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

E15 - The Maternal Capacitance

Aired: February 09, 2009

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

E16 - The Cushion Saturation

Aired: March 02, 2009

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

E17 - The Terminator Decoupling

Aired: March 09, 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.

E18 - The Work Song Nanocluster

Aired: March 16, 2009

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

E19 - The Dead Hooker Juxtaposition

Aired: March 30, 2009

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

E20 - The Hofstadter Isotope

Aired: April 13, 2009

A fellow comic book enthusiast's hitting on Penny leads to Leonard and Howard going to a bar's Ladies' Night.

E21 - The Vegas Renormalization

Aired: April 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.

E22 - The Classified Materials Turbulence

Aired: May 04, 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.

E23 - The Monopolar Expedition

Aired: May 11, 2009

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