The Big Bang Theory

After returning from the North Pole, a conflict among the guys sends Sheldon back to Texas and interferes with Leonard's reunion with Penny.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

Leonard and Penny's first night together goes awkwardly. Sheldon and Howard wager on the species of a cricket.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Jim Reynolds

Sheldon attempts to covertly alter Penny's habits, while Howard and Raj try their luck meeting women at a Goth-style club.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Maria Ferrari

When Raj has to find a new job or be sent back to India, Sheldon's solution leaves Leonard and Penny dealing with Howard as the third wheel.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steve Holland

Leonard is forced to ask Penny to set Howard up with one of her friends, while Sheldon seeks payback against sci-fi star Wil Wheaton.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Lee Aronsohn

Leonard tries to learn about football to fit in with Penny's friends. Meanwhile, a loss in a kite war threatens to end Raj and Howard's friendship.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, David Goetsch

Sheldon is caught in the middle when Leonard and Penny argue about Penny's friend staying at her apartment.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Richard Rosenstock

Penny is forced to turn to Sheldon for help when she dislocates her shoulder in the bathtub. Meanwhile, the rest of the guys accidentally get stoned in the desert while waiting for a meteor shower.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

Sheldon plans revenge after Kripke humiliates him on the radio. Howard develops doubts about his relationship with Bernadette.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Richard Rosenstock

Sheldon attempts to help Penny understand physics to impress Leonard, while Howard becomes jealous when Bernadette takes an interest in Leonard's research.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

Leonard's mother makes a visit to his dismay and Sheldon's delight.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, David Goetsch

Raj talks Sheldon into being his wingman at a university mixer. Leonard has trouble dealing with Penny consulting a psychic.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Eric Kaplan

When their apartment is robbed, Leonard and Sheldon turn to Howard and Raj to create a state-of-the-art security system.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

Sheldon wreaks havoc when he is stumped by a difficult physics question.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

When Leonard is offered a trip to Switzerland on Valentine's Day to visit the CERN laboratory, Sheldon uses any and all means to be his guest instead of Penny.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Lee Aronsohn

Sheldon misses an opportunity to get Stan Lee's autograph because he has to make an appearance in traffic court.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Peter Chakos
Writer(s): Chuck Lorre, Bill Prady, Steve Holland

The guys' friendship is threatened when they find a ring from the "Lord of the Rings" trilogy.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

Sheldon seeks help from the rest of the gang in overcoming his fear of public speaking when he receives an award.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Eric Kaplan

Sheldon takes on Wil Wheaton in a game of bowling. Leonard and Penny's relationship comes to a crossroad.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, David Goetsch

Sheldon is forced to go behind Leonard's back to spend time with Penny following their breakup.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Anthony Rich
Writer(s): Chuck Lorre, Bill Prady, Lee Aronsohn

Chaos ensues when a nymphomaniac physicist visiting Sheldon hooks up with Leonard.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, Steven Molaro

Leonard tells Penny about how he and Sheldon became roommates and what happened to the elevator.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Mark Cendrowski
Writer(s): Chuck Lorre, Bill Prady, David Goetsch

Penny has a night of angry, drunken sex with Leonard, much to his confusion. Meanwhile, Howard and Raj search for Sheldon's perfect match online.

Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco
Director(s): Peter Chakos
Writer(s): Chuck Lorre, Bill Prady, Lee Aronsohn