Summary: Mensa-fied best friends and roommates Leonard and Sheldon, physicists who work at the California Institute of Technology, may be able to tell everybody more than they want to know about quantum physics, but getting through most basic social situations, especially ones involving women, totally baffles them. How lucky, then, that babe-alicious waitress/aspiring actress Penny moves in next door. Frequently seen hanging out with Leonard and Sheldon are friends and fellow Caltech scientists Wolowitz and Koothrappali. Will worlds collide? Does Einstein theorize in the woods?
|Episode Online Video|
S01, E11 (First Aired:
Leonard and the boys avoid Sheldon when he gets sick, leaving Penny to nurse him back to health.
S01, E12 (First Aired:
Sheldon and Leonard look for a way to derail a 15-year-old physics prodigy's research.
S01, E13 (First Aired:
When Sheldon tries to prove his mental superiority as they train for the Physics Bowl, the guys kick him off the team and bring his nemesis (Sara Gilbert) aboard.
S01, E14 (First Aired:
Leonard and the guys buy a time machine prop from a classic movie; Penny tells the guys their obsession with comics and toys is pathetic.
S01, E15 (First Aired:
Leonard devises a plan to eliminate his rivals when he, Wolowitz and Koothrappali all fall for Sheldon's twin sister, but his plan backfires when Sheldon decides to choose who his sister dates.
S01, E16 (First Aired:
Penny learns that Leonard does not celebrate birthdays, so she plans a surprise party; Sheldon unexpectedly gets to live out one of his biggest fantasies in an electronics store.
S01, E17 (First Aired:
When Leonard finally works up the courage to ask Penny out on a date, they each turn to Sheldon for advice.
S02, E01 (First Aired:
Penny's first date with Leonard goes awry; Penny finds Sheldon to be an unwilling confidant.
S02, E02 (First Aired:
After seeing Penny with a handsome new guy, Leonard rushes into a rebound relationship with Sheldon's nemesis, Leslie Winkle.
S02, E04 (First Aired:
Raj gets an inflated ego and makes a play for Penny after being referenced in a magazine article.
S10, E02 (First Aired:
Wolowitz has a meeting with Colonel Williams, a representative from the Air Force Department of Material Command.
S02, E05 (First Aired:
Leonard and his friends stage an intervention to force Sheldon to face his fear of driving.
S02, E06 (First Aired:
Sheldon and the gang are confused when a young grad student is attracted to him.
S02, E07 (First Aired:
When Sheldon bans Penny from the apartment for a series of petty infractions, Penny vows to get revenge.
S02, E08 (First Aired:
Leonard inadvertently steals away the new woman Wolowitz thinks is the love of his life.
S02, E09 (First Aired:
Sheldon is thrilled when Leonard starts dating a woman who meets Sheldon's stringent standards.
S02, E10 (First Aired:
Leonard asks Penny for advice when his new relationship starts moving too fast.
S02, E11 (First Aired:
Penny starts dating Leonard's handsome colleague; Leonard and his friends are tortured by Sheldon's obsession with gift-giving etiquette.
S02, E12 (First Aired:
When Penny's comment about Wolowitz's love life sends him into a depressed stupor, his friends lose their most important teammate in an upcoming fighting-robot competition.
S02, E13 (First Aired:
Sheldon develops a scientific procedure for making friends; Kripke controls a new supercomputer.
S02, E14 (First Aired:
Sheldon's solution to Penny's financial difficulty leads to a confrontation between Leonard and Penny's ex-boyfriend.
S02, E15 (First Aired:
Leonard and Penny are drawn together after a disastrous visit from Leonard's mother (Christine Baranski).
S02, E16 (First Aired:
A paintball game leads to a fight between Sheldon and Penny, and romance for Leslie and Wolowitz.
S02, E17 (First Aired:
Leonard, Sheldon and Wolowitz are ecstatic to learn that a famous science-fiction actress (Summer Glau) is aboard the train they are taking to San Francisco.
S02, E18 (First Aired:
Penny's home business turns into a complete nightmare when Sheldon takes over.
S02, E19 (First Aired:
Penny develops a rivalry with a sexy new female neighbor who threatens her position as queen bee of the building.
S02, E21 (First Aired:
Koothrappali and Leonard take Wolowitz to Las Vegas; Sheldon is forced to bunk with Penny when he gets locked out of his apartment.
S02, E22 (First Aired:
Penny makes a surprising revelation about Leonard while on her date with Stuart; Wolowitz finds a critical design flaw in his NASA project.
S02, E23 (First Aired:
While Leonard prepares for a three-month science expedition, he and Penny re-evaluate their feelings for each other.
S03, E01 (First Aired:
After tampering with Sheldon's Arctic-expedition data, the guys follow him back to Texas, which threatens Leonard's chances for romance with Penny.
S03, E02 (First Aired:
Penny and Leonard try to recover from an awkward hookup; Howard and Sheldon make a high-stakes bet.
S03, E03 (First Aired:
Howard and Raj hit a Goth nightclub to meet women; Sheldon tries chocolate-based behavior modification on Penny.
S03, E04 (First Aired:
Raj faces deportation if he does not find a job; Leonard and Penny deal with Howard as a third wheel.
S03, E05 (First Aired:
Sheldon seeks revenge on his nemesis, Wil Wheaton; Wolowitz wants Penny to set him up with one of her friends.
No Episode Title
A free-spirited beauty moves in next door to two physicists.
S03, E06 (First Aired:
Sheldon teaches Leonard how to understand football; a kite-fighting incident threatens Howard and Raj's friendship.
S03, E08 (First Aired:
Penny is forced to rely on Sheldon when she is injured while Howard, Leonard and Raj are away.
S03, E09 (First Aired:
After being humiliated on the radio, Sheldon vows to destroy Kripke; Wolowitz tries to not ruin his new relationship with Bernadette.
S03, E10 (First Aired:
Sheldon tries to help Penny understand Leonard's work; Wolowitz gets jealous when Leonard starts hanging out with his new girlfriend.
S03, E12 (First Aired:
Sheldon and Koothrappali attend a university mixer; Leonard discovers that Penny believes in psychics.
S03, E13 (First Aired:
After their apartment is robbed, Leonard and Sheldon turn to their friends to create a state-of-the-art security system.
S03, E14 (First Aired:
Sheldon tries to figure out the answer to a physics problem by working with Penny.
S03, E15 (First Aired:
Leonard must choose who to bring with him when he goes to see the Large Hadron Collider on Valentine's Day.
S03, E17 (First Aired:
When the guys buy a ring from ``The Lord of the Rings'' at a garage sale, the item threatens to tear them apart.
S03, E19 (First Aired:
Penny and Leonard have a fight that threatens their relationship; Sheldon and Wil Wheaton face off once again.