Wizard physicist and all round hunk David Underhill starts working with Leonard. She tries helping Sheldon with a ringing in his ear, but is unable to help him. Stephanie Barnett has moved in with Leonard and Sheldon, according to their roommate contract, though Leonard denies that she is living with them. He tries to force himself into conversations with 'urban slang' to 'help' Leonard in the relationship with Stephanie.

Sheldon is concerned that Stephanie is the only girl Leonard has dated that he 'finds tolerable'. Stephanie and Leonard then hitch up, alienating Howard. Wolowitz invites Stephanie to drive the Mars rover, which winds up stuck in a ditch. A war escalates between them.ДЄ smitten Wolowitz thinks he's found his soul mate-until the woman, Dr. Sheldon banishes Penny from the apartment when she accumulates three strikes from him. The loss of his freedom and leisure time upsets Sheldon but he can't stop her. Sheldon alienates all his possible chauffeurs and is forced to try to learn to drive.ДЄ grad student, Ramona Nowitzki, begins pushing Sheldon to concentrate all his spare time on his scientific endeavours. Leonard is working nights at the university and can't drive Sheldon to work. The fame soon goes to his head and he alienates all his friends. Raj discovers a trans-neptunian planetoid and gets featured in People Magazine as a result. Sheldon learns that Penny is frustrated by her failures in life. Sheldon becomes distracted from playing Age of Conan by Penny who has accidentally attempted to use her car keys to open her apartment door. Sheldon hates Leslie and resents being exiled to the staircase to play Mario alone.

Penny is dating a new guy, so Leonard jumps at the chance to date Leslie Winkle again. Sheldon with Penny on the stairs while playing Mario. She confesses to Sheldon about dropping out of college and he can't take the pressure of keeping her secret. Penny and Leonard return from their date, but she gives him a brush off when he tries to get a second date.

Kunal Nayyar as Rajesh KoothrappaliВ (23/23).

Simon Helberg as Howard WolowitzВ (23/23).

Johnny Galecki as Leonard HofstadterВ (23/23).

Season 2 of The Big Bang Theory returned to television in September 22, 2008, and contained 23 episodes. Howard's character remains similar to that of season one in his attempts to seduce women, & lastly Rajesh manages to briefly communicate an apology to Penny without having consumed alcohol. In the season finale Penny hints at her true feelings for Leonard.

Soon their relationship progresses into a stronger friendship than before, while Sheldon and Penny's friendship slowly begins. Leonard and Penny's relationship takes a turn for the worse when they break up, but is quickly resolved. SeasonВ 2 deals with character development, including Sheldon becoming more and more obsessive.

Big bang theory season 2 episode 21