The Bad Fish Paradigm
Series 2, Episode 1 PG
CC
HD
CC
SD
In the second season premiere, after her first date with Leonard goes awry, Penny finds an unwilling confidant in Leonard's anti-social roommate, Sheldon.
The Codpiece Topology
Series 2, Episode 2 PG
CC
HD
CC
SD
Penny and Leonard compete to see who will be the first to move on after their breakup. When Leonard sees Penny with a handsome new guy (guest star TRAVIS SCHULDT Scrubs), he enters into a rebound relationship with Sheldon's nemesis, Leslie Winkle (series regular SARA GILBERT).
The Barbarian Sublimation
Series 2, Episode 3 PG
CC
HD
CC
SD
Sheldon creates a monster when he introduces Penny to the world of online gaming. Especially when her addiction wreaks havoc on his life.
The Griffin Equivalency
Series 2, Episode 4 PG
CC
HD
CC
SD
Raj's ego puts all of his friendships in jeopardy when he gets an inflated sense of self. Newly famous because of an article in a magazine, Raj (series regular KUNAL NAYYAR) makes a disastrous play for Leonards longtime crush, Penny.
The Euclid Alternative
Series 2, Episode 5 PG
CC
HD
CC
SD
Leonard and his friends stage an intervention to make Sheldon confront his longstanding fear of driving.
The Cooper-Nowitzki Theorem
Series 2, Episode 6 PG
CC
HD
CC
SD
A young grad student’s attraction to Sheldon confuses everyone – including Sheldon himself.
The Panty Pinata Polarization
Series 2, Episode 7 PG
CC
HD
CC
SD
Sheldon and Penny engage in a battle of wills as Penny vows to get revenge on Sheldon when he bans her from the apartment for a series of petty infractions.
The Lizard-Spock Expansion
Series 2, Episode 8 PG
CC
HD
CC
SD
Wolowitz (series regular SIMON HELBERG) thinks he's found the love of his life (guest star SARA RUE) until she meets Leonard.
The White Asparagus Triangulation
Series 2, Episode 9 PG
CC
HD
CC
SD
Sheldon can barely contain his joy when Leonard starts dating a woman (SARA RUE) who meets Sheldon's exacting standards.
The Vartabedian Conundrum
Series 2, Episode 10 PG
CC
HD
CC
SD
Leonard just can't say no. When his relationship with new girlfriend, Stephanie starts moving too fast, Leonard turns to Penny for advice.
The Bath Item Gift Hypothesis
Series 2, Episode 11 PG
CC
HD
CC
SD
Leonards handsome colleague starts dating Penny. And Leonard's friends are being tormented by Sheldon's obsession with gift-giving etiquette.
The Killer Robot Instability
Series 2, Episode 12 PG
CC
HD
CC
SD
When Pennys comment about Wolowitzs love life sends him into a depressed stupor, his friends lose their most important teammate in an upcoming fighting robot competition.
The Friendship Algorithm
Series 2, Episode 13 PG
CC
HD
CC
SD
Socially awkward Sheldon develops a scientific procedure for making friends.
The Financial Permeability
Series 2, Episode 14 PG
CC
HD
CC
SD
Sheldon's "simple" solution to Penny's financial problem leads to a confrontation between Leonard and Penny's hulking ex-boyfriend, Kurt (guest star BRIAN PATRICK WADE).
The Maternal Capacitance
Series 2, Episode 15 PG
CC
HD
CC
SD
A disastrous visit from Mrs. Hofstadter (special guest star CHRISTINE BARANSKI) brings Leonard and Penny closer together.
The Cushion Saturation
Series 2, Episode 16 PG
CC
HD
CC
SD
A paintball game has surprising consequences for Leonard and his friends when it leads to a fight between Penny and Sheldon – and romance for Wolowitz and Leslie.
The Terminator Decoupling
Series 2, Episode 17 PG
CC
HD
CC
SD
A train trip to San Francisco takes a major detour when Leonard, Sheldon, Wolowitz and Raj discover that beautiful sci-fi actress SUMMER GLAU ("Terminator") is onboard.
The Work Song Nanocluster
Series 2, Episode 18 PG
CC
HD
CC
SD
Penny’s home hair products business becomes a complete nightmare when a caffeine-addled Sheldon takes over.
The Dead Hooker Juxtaposition
Series 2, Episode 19 PG
CC
HD
CC
SD
There’s a new queen bee in the building! Penny develops a rivalry with a sexy female neighbor who moves into the building and threatens to become the “new Penny.”
The Hofstadter Isotope
Series 2, Episode 20 PG
CC
HD
CC
SD
While Stuart (guest star KEVIN SUSSMAN), a fellow comic book-loving pal of the guys, romances Penny, Leonard and Wolowitz venture out into the world of "Ladies' Night" at a local bar.
The Vegas Renormalization
Series 2, Episode 21 PG
CC
HD
CC
SD
Leonard and Koothrappali take a heartbroken Wolowitz to Las Vegas, leaving Sheldon locked out of his apartment and forced to bunk with Penny.
The Classified Materials Turbulence
Series 2, Episode 22 PG
CC
HD
CC
SD
Things begin to look up for Leonard when Penny makes a surprising revelation on her second date with Stuart (guest star KEVIN SUSSMAN). Meanwhile, Wolowitz enlists his friends' help when he discovers a critical design flaw in his project for NASA.
The Monopolar Expedition
Series 2, Episode 23 PG
CC
HD
CC
SD
On the second season finale, Leonard and Penny reconsider their feelings for one another. When Leonard and his friends decide to spend the summer working – at the North Pole – Penny is conflicted.