Episode 1: The Bad Fish Paradigm; 9/22/08
Penny surprisingly turns to Sheldon as a confidant after her disastrous first date with Leonard.
Episode 2: The Codpiece Topology; 9/29/08
A jealous Leonard reacts to Penny's new guy by rebounding with Leslie.
Episode 3: The Barbarian Sublimation; 10/6/08
Sheldon shows Penny the joys of online gaming, creating an addict in the process.
Episode 4: The Griffin Equivalency; 10/13/08
Raj gets an ego boost after winning some fame from a magazine article and risks his friendship with Leonard by trying to win over Penny.
Episode 5: The Euclid Alternative; 10/21/08
The friends band together to help Sheldon face his fear of driving.
Episode 6: The Cooper-Nowitzki Theorem; 11/4/08
The gang is puzzled by a young grad student's attraction to Sheldon.
Episode 7: The Panty Pinata Polarization; 11/10/08
It's an all-out war between Penny and Sheldon when he bans her from the apartment for what she thinks are petty infractions.
Episode 8: The Lizard-Spock Expansion; 11/17/08
A smitten Wolowitz thinks he's found his soul mate---until the woman (Sara Rue) meets Leonard.
Episode 9: The White Asparagus Triangulation; 11/24/08
Sheldon is ecstatic when Leonard begins dating Stephanie (Sara Rue), who meets all of Sheldon's seemingly impossible standards.
Episode 10: The Vartabedian Conundrum; 12/9/08
Leonard's relationship with Stephanie is moving too fast for him, so he runs to Penny for advice.
Episode 11: The Bath Item Gift Hypothesis; 12/16/08
Christmas brings no tidings of comfort and joy to Leonard, whose colleague starts dating Penny. Meanwhile, Sheldon drives everyone crazy over his adherence to gift-giving etiquette.
Episode 12: The Killer Robot Instability; 1/12/09
Penny wounds Wolowitz with a comment about his love life, prompting him to abandon friends who need him for a fighting-robot contest.
Episode 13: The Friendship Algorithm; 1/19/09
Here's a conundrum to baffle the guys: Sheldon's intelligence, which renders him socially awkward, is also the source of his new scientific procedure for making friends.
Episode 14: The Financial Permeability; 2/2/09
Sheldon helps Penny with a financial crisis, but his solution leads to a confrontation between Leonard and Penny's burly ex-boyfriend Kurt.
Episode 15: The Maternal Capacitance; 2/9/09
Leonard suffers through a dreadful visit from his mother (Christine Baranski) that ends up bringing him and Penny closer.
Episode 16: The Cushion Saturation; 3/2/09
A paintball game has Penny and Sheldon engaging in their own personal battle and Leslie and Wolowitz finding romance.
Episode 17: The Terminator Decoupling; 3/9/09
The guys' trip to San Francisco takes a detour once they learn that actress Summer Glau (appearing as herself) is on their train.
Episode 18: The Work Song Nanocluster; 3/17/09
Penny starts a hair-product business that suffers when her friends, particularly Sheldon, become involved.
Episode 19: The Dead Hooker Juxtaposition; 3/30/09
Penny develops a rivalry with a pretty woman who moves into the building.
Episode 20: The Hofstadter Isotope; 4/14/09
Penny is romanced by a friend of the guys' while at a comic-book store. Meanwhile, Leonard and Wolowitz search for love at a bar's ladies' night.
Episode 21: The Vegas Renormalization; 4/28/09
Leonard, Koothrappali and Wolowitz go to Las Vegas, and Sheldon is locked out of the apartment, leaving him no choice but to stay with Penny.
Episode 22: The Classified Materials Turbulence; 5/4/09
While on a date with Stuart, Penny makes an unexpected discovery regarding Leonard; and Wolowitz asks for his friends' help on his NASA project when he uncovers a design flaw.
Episode 23: The Monopolar Expedition; 5/11/09
Leonard gets ready for a three-month long science trip, and he and Penny come to terms with their feelings for each other.
