The Big Bang Theory Episode Guide

Season 1 (2007 - 2008)

Premeire: Pilot

In the pilot, life is about to change for two geniuses, Sheldon and Leonard when the beautiful Penny moves in across the hall. Leonard sees potential love interest in Penny and offers to retrieve her television from her ex-boyfriend.

Finale: The Tangerine Factor

Penny breaks up with her boyfriend after he posted intimate details about her on his blog. Leonard tries to comfort her but accidentally sends her back into the arms of her boyfriend.

Season 2 (2008 - 2009)

Premeire: The White Asparagus Triangulation

Sheldon tries to secure Leonard's relationship with Stephanie and sets up a scenario where Leonard can prove he's the alpha male.

Finale: The Monopolar Expedition

When Sheldon gets news he's going to the North Pole on a NSF expedition, he invites the guys as his group.

Season 3 (2009 - 2010)

Premeire: The Electric Can Opener Fluctuation

Sheldon runs to his mother when he learns the gang messed with her arctice expedition's data; the guys go chasing after him with Leonard sacrificing his chance with Penny.

Finale: The Staircase Implementation

Leonard tells Penny the story of how the apartment elevator broke through a series of flashbacks.

Season 4 (2010 - 2011)

Premeire: The Robotic Manipulation

Penny tags along for Sheldon's first date on the fourth season premiere. Elsewhere, Wolowitz discovers a new use for a robotic arm.

Finale: The Roommate Transmogrification

Raj moves in with Sheldon on the fourth season finale of The Big Bang Theory. This takes Penny by surprise.

Season 5 (2011 - 2012)

Premeire: The Skank Reflex Analysis

The Big Bang Theory is back! On the premiere, the gang deals with Penny and Raj actually sleeping together.

Finale: The Countdown Reflection

The gang must hurry to plan a wedding when Howard and Bernadette decide to have the event before the NASA launch on the season finale of The Big Bang Theory.

Season 6 (2012 - 2013)

Premeire: The Date Night Variable

His friends all go on dates to kick off The Big Bang Theory Season 6. As a result, Raj must face his loneliness.

Finale: The Bon Voyage Reaction

In the season 6 finale of The Big Bang Theory, Penny and Sheldon are shocked when Leonard considers taking a great job opportunity overseas.