Mark Cendrowski

Leonard and Sheldon are brilliant physicists, socially inept outside of the lab. It's up to free-spirited neighbor Penny to teachthem a thing or two about life. While Leonard spends his days looking for love, Sheldon is quite content with their ever-expandinguniverse of friends, including fellow scientists Raj, Howard and Howard's new fiancée, Bernadette and Penny's "bestie" Amy FarrahFowler.

Worlds collided last season, when a love affair with Penny (Kaley Cuoco) opened a big, wide, wonderful world of romance for Leonard (Johnny Galecki). Sheldon (Jim Parsons), of course, likes the world just the way it is, thank you. But now, that Leonard and Penny have broken up again, they can test the variables of being neighbors once more.

Creator/producers Chuck Lorre ("Two and a Half Men") and Bill Prady ("Dharma & Greg") make comedy a science with the second big season of THE BIG BANG THEORY that makes room for new series regular Sara Gilbert (who starred on "Roseanne" with series star Galecki). Check out the physics of funny!

Worlds collided last season, when a love affair with Penny (Kaley Cuoco) opened a big, wide, wonderful world of romance for Leonard (Johnny Galecki). Sheldon (Jim Parsons), of course, likes the world just the way it is, thank you. But now, that Leonard and Penny have broken up again, they can test the variables of being neighbors once more.