Season 2

Season 2 of The Big Bang Theory premiered on September 22, 2008, and has 23 episodes. 
It deals with character development and relationships.
Sheldon becoming more and more obsessive. Leonard and Penny's relationship takes a turn for the worse when they temporarily break up and reconcile. Soon their relationship progresses into a stronger friendship than before, while Sheldon and Penny's friendship slowly begins. In the season finale Penny hints at her true feelings for Leonard. Howard remains similar to that of season one in his attempts to seduce women, & lastly Raj manages to briefly communicate an apology to Penny without having consumed alcohol. 
==Cast==
=== Main Cast ===
* Johnny Galecki as Leonard Hofstadter (23/23)
* Jim Parsons as Sheldon Cooper (23/23)
* Kaley Cuoco as Penny (23/23)
* Simon Helberg as Howard Wolowitz (23/23)
* Kunal Nayyar as Rajesh Koothrappali (23/23)
* Sara Gilbert as Leslie Winkle (4/23)
=== Recurring Cast ===
* Carol Ann Susi as Debbie Wolowitz (6/23)
* Mark Harelik as Eric Gablehauser (3/23)
* Brian George as V. M. Koothrappali (2/23)
* Alice Amter as Mrs. Koothrappali (2/23)
* John Ross Bowie as Barry Kripke (2/23)
* Sara Rue as Stephanie Barnett (3/23)
* Kevin Sussman as Stuart Bloom (2/23)
* Ian Scott Rudolph as Captain Sweatpants (2/23)
=== Guest Cast ===
* Christine Baranski as Beverly Hofstadter
* Brian Patrick Wade as Kurt
* Travis Schuldt as Eric
* Charlie Sheen as himself
* Octavia Spencer as DMV employee
* Riki Lindhome as Ramona Nowitzki
* Lio Tipton as themself
* Emily Happe as Kathy O'Brien
* Samantha Potter as Herself
* Michael Trucco as David Underhill
* Summer Glau as Herself
* George Smoot as Himself
* Valerie Azlynn as Alicia
* Jody Lyn O'Keefe as Mikayla
==Episodes==
Episode (Series)</font>	Episode (Season/Ep#)</span>	Title 	Original Air Date 	Directed By 	Description
18 	201 	The Bad Fish Paradigm 	September 22, 2008	Mark Cendrowski	Penny and Leonard return from their date, but she gives him a brush off when he tries to get a second date. She confesses to Sheldon about dropping out of college and he can't take the pressure of keeping her secret.
19 	202 	The Codpiece Topology 	September 29, 2008	Mark Cendrowski	Sheldon with Penny on the stairs while playing Mario. Penny is dating a new guy, so Leonard jumps at the chance to date Leslie Winkle again. Sheldon hates Leslie and resents being exiled to the staircase to play Mario alone.
20 	203 	The Barbarian Sublimation 	October 6, 2008 	Mark Cendrowski	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 learns that Penny is frustrated by her failures in life.
21 	204 	The Griffin Equivalency 	October 13, 2008 	Mark Cendrowski	Raj discovers a trans-neptunian planetoid and gets featured in People Magazine as a result. The fame soon goes to his head and he alienates all his friends.
22 	205 	The Euclid Alternative 	October 20, 2008 	Mark Cendrowski	
Leonard is working nights at the university and can't drive Sheldon to work. Sheldon alienates all his possible chauffeurs and is forced to try to learn to drive.
23 	206 	The Cooper-Nowitzki Theorem 	November 3, 2008 	Mark Cendrowski	A grad student, Ramona Nowitzki, begins pushing Sheldon to concentrate all his spare time on his scientific endeavours. The loss of his freedom and leisure time upsets Sheldon but he can't stop her.
24 	207 	The Panty Piñata Polarization 	November 10, 2008 	Mark Cendrowski	Sheldon banishes Penny from the apartment when she accumulates three strikes from him. A war escalates between them.
25 	208 	The Lizard-Spock Expansion 	November 17, 2008 	Mark Cendrowski	A smitten Wolowitz thinks he's found his soul mate—until the woman, Dr. Stephanie Barnett, meets Leonard. Wolowitz invites Stephanie to drive the Mars rover, which winds up stuck in a ditch. Stephanie and Leonard then hitch up, alienating Howard.
26 	209 	The White Asparagus Triangulation 	November 24, 2008 	Mark Cendrowski	Sheldon is concerned that Stephanie is the only girl Leonard has dated that he "finds tolerable". He tries to force himself into conversations with "urban slang" to "help" Leonard in the relationship with Stephanie.
27 	210 	The Vartabedian Conundrum 	December 8, 2008 	Mark Cendrowski	Stephanie Barnett has moved in with Leonard and Sheldon, according to their roommate contract, though Leonard denies that she is living with them. She tries helping Sheldon with a ringing in his ear, but is unable to help him.
28 	211 	The Bath Item Gift Hypothesis 	December 15, 2008 	Mark Cendrowski	Wizard physicist and all round hunk David Underhill starts working with Leonard. He soon asks Penny out much to Leonard's distress.
29 	212 	The Killer Robot Instability 	January 12, 2009 	Mark Cendrowski	Howard builds a robot called MONTE (Mobile Omnidirectional Neutralization and Termination Eradicator) to enter into the Southern California Robot Fighting League Round Robin Invitational. When Penny tells Howard what she really thinks of his sleazy come-ons, he is hurt and becames distraught; Leonard makes Penny apologize.
30 	213 	The Friendship Algorithm 	January 19, 2009 	Mark Cendrowski	Socially awkward, Sheldon develops a scientific procedure (the titular "Friendship Algorithm") for making friends. He needs to use an open science grid computer that is in Barry Kripke's office, but Leonard tells Sheldon that only Barry's friends can use it.
31 	214 	The Financial Permeability 	February 2, 2009 	Mark Cendrowski	Penny is short on her rent money and so Sheldon lends her some of his spare cash. She feels guilty about not paying it back and still can't pay her electricity bills. Leonard tries to help and discovers that she paid her an $1800 fine for Kurt. Leonard tries and get the money back for her.
32 	215 	The Maternal Capacitance 	February 9, 2009 	Mark Cendrowski	Leonard's mother (Dr. Beverly Hofstadter) comes to visit. She is a cold, analytical psychiatrist. She drives Penny and Leonard to drink with her psychoanalysis while Sheldon loves her.
33 	216 	The Cushion Saturation 	March 2, 2009 	Mark Cendrowski	Penny accidentally shoots Sheldon's sofa cushion with a paint ball gun. He is deeply disturbed by this turn of events and is not happy with the cushion even once it has been dry cleaned. Meanwhile Howard starts sleeping with Leslie Winkle.
34 	217 	The Terminator Decoupling 	March 9, 2009 	Mark Cendrowski	A train trip to a conference in San Francisco takes a major detour when Leonard, Sheldon, Wolowitz, and Raj discover that their favorite sci-fi actress, Summer Glau, is on board. Also Sheldon must let Penny enter his room to email him a scientific paper.
35 	218 	The Work Song Nanocluster 	March 16, 2009 	Peter Chakos 	Penny starts her own business and asks Sheldon for help. The other guys become involved and they end up spending all night trying to ship an order for one thousand “Penny Blossoms”.
36 	219 	The Dead Hooker Juxtaposition 	March 30, 2009 	Mark Cendrowski	A new tenant, Alicia, moves in to the apartment above the guys. Sheldon's only concern is with the noise she might make. Where as the other guys are all too quick to help her out with all her needs. Penny becomes increasingly jealous of the way they treat her and losing her queen bee status.
37 	220 	The Hofstadter Isotope 	April 13, 2009 	Mark Cendrowski	It's "Anything Can Happen Thursday" for the guys and they end up with Penny at the comic book store. She goes on a date with the owner Stuart and Leonard is jealous. He suggests that they all head to a bar to meet women.
38 	221 	The Vegas Renormalization 	April 27, 2009 	Mark Cendrowski	Leslie ends her friends with benefits relationship with Howard. Sheldon suggests the guys go to Vegas to help Howard get over the pain. They do and end up hiring a prostitute to give Howard the Jewish girlfriend role playing treatment.
39 	222 	The Classified Materials Turbulence	May 4, 2009 	Mark Cendrowski	Howard has designed a special toilet for the International Space Station. He realizes that it is going to malfunction and asks the guys to help him fix it. Stuart has another date with Penny and asks Leonard for advice.
40 	223 	The Monopolar Expedition 	May 11, 2009 	Mark Cendrowski	After Sheldon wakes up the president of Caltech in the middle of the night simply to ask a question, he is offered to spend three months doing research on the North Pole in an attempt to prove the validity of string theory. Leonard, Howard and Raj are first overjoyed and then end up going with him. Penny is very upset about Leonard leaving, but can't tell him that.
==Reception==
Season Two received better ratings than the previous season, with an average of 10 million views per episode.
==Gallery==
Season 2 Promo Pic.jpg|The gang.
Johnny Galecki 2008.jpg|Leonard Hofstadter
Sheldon Cooper 2008.png|Sheldon Cooper
Kaley-Cuoco.jpg|Penny
Howard1.jpg|Howard Wolowitz
Raj.jpg|Rajesh Koothrappali
The Big Bang Theory Mondays Ad (CBS, 2008-2009).jpg
The Big Bang Theory The Second Season.jpg
Category:Season 2 (The Big Bang Theory)
Category:Seasons
Season 02
Category:Sheldon Cooper
Category:Penny
Category:Leonard Hofstadter
Category:Howard Wolowitz
Category:Rajesh Koothrappali
Category:Stuart
Category:Beverly Hofstadter
de:Staffel 2
es:Segunda temporada
it:Seconda stagione
pt-br:2ª temporada