Johnny Galecki

The Big Bang Theory: The Twelfth and Final Season: Leonard and Sheldon are brilliant physicists – geniuses in the laboratory but socially challenged everywhere else. Enter beautiful, street-smart neighbor Penny, who aims to teach them a thing or two about life. Despite their on-again, off-again relationship in the past, Leonard and Penny have finally gotten married. Even Sheldon has found a female companion, entering into a “relationship agreement” with neurobiologist Amy Farrah Fowler, and he recently took their relationship to the next level by marrying her after a long courtship.

Leonard and Sheldon are brilliant physicists geniuses in the laboratory but socially challenged everywhere else. Enter beautiful, street-smart neighbor Penny, who aims to teach them a thing or two about life. Despite their on-again, off-again relationship in the past, Leonard and Penny have finally gotten married. Even Sheldon has found a female companion, entering into a relationship agreement with neurobiologist Amy Farrah Fowler, and he recently took their relationship to the next level by proposing marriage.

The universe of Drs. Leonard Hofstadter and Sheldon Cooper is endlessly complicated and hilarious as The Big Bang Theory enters the tenth dimension! Last season, Leonard and Penny went from next-door neighbors to next-door newlyweds with a nuptial excursion to Vegas. This season, they find themselves in a repeating paradigm as they re-create their wedding this time with family including Pennys mother (Katey Sagal) and brother (Jack McBrayer) and Leonards parents (Christine Baranski & Judd Hirsch).

Prepare to enter phase nine of television's perpetual laughter experiment as The Big Bang Theory successfully fuses the elements of science and sitcom. Our two genius roommates - Leonard and Sheldon - and their friends are back once again (smarter, but no wiser). Last season, Sheldon went soul-searching (on a train, of course) and was prepared to make some substantial revisions on his Relationship Agreement with Amy, when everything changed. Leonard, meanwhile, was off to Vegas with Penny to finally tie the knot in the season finale.

Sheldon is rescued from his soul-searching cross-country train trip (older but no wiser), and that means The Big Bang Theory gang's all here to spread another year's cheer as TV's most attended laugh seminar. Enroll in the comic curriculum to observe Leonard's minor surgery, which signals a major catastrophe for Sheldon, Howard's obsession over his mom's relationship with friend-turned-freeloader Stuart, and the unexpected results of Penny's technique as a pharmaceutical sales rep.

Socially challenged they remain, but the scientific geniuses of The Big Bang Theory always deliver hilarious results. Leonard returns from his North Sea expedition to find that his relationship with Penny involves more beta-testing than he's ever done in a lab. Howard's attachment issues with the women in his life in particular and Raj's social breakthrough with women in general provide more laughs. Bernadette and Amy stand staunchly by the men in their life, even when they're sitting in marathon role-playing games.

Whether on Earth or above it, hilarity is outrageously universal in TV's most popular comedy featuring four forward-thinking but socially backward geniuses. Fun discoveries multiply: Leonard learns jealousy is bad for a relationship (with Penny) but science is good for seduction (of Penny). Howard finds life on the International Space Station is no escape from terrestrial turmoil between his overbearing mom and his new wife Bernadette. Raj meets someone special who may be a good match, if only he can keep her from fleeing mid-date.

The geniuses of The Big Bang Theory get thrown for a bell curve in all 24 episodes of the phenomenally funny fifth season of the hit show. In "TV's top-rated comedy" (New York Post), Penny and Leonard's relationship is relaunched in full "Beta Test" mode, while Sheldon, Howard and Raj discover the feminine mystique is something that cannot be easily graphed or calculated.

"Four seasons in, it is still laugh-out-loud funny. Every episode, every week," says USA Today's Robert Bianco about the hit series The Big Bang Theory. Subject his conclusion to empirical analysis by watching all 24 episodes of season four on 3 discs. This season, the Big Bang gang's romantic universe expands. On the rebound from Penny, Leonard falls for Raj's sister Priya. Sheldon gets a girlfriend - Amy, a dour neurobiologist who declares herself Penny's BFF. Howard and Bernadette heat up; meanwhile, Raj is romancing her in Bollywood daydreams.