Returned: March 17 (airs Mondays at 8 pm/ET, CBS)

Number of new episodes: 7 Where we left off: Quantum physicists Leonard and Sheldon weren't any closer to scoring with the ladies when the WGA strike hit. But they had their hot gal pal Penny to help them acquire social skills and loosen up. What's next: Sheldon falls sick, but he's such a bad patient Leonard avoids him completely. The benefit for Sheldon is he gets Penny as a nurse. Will they or won't they?: Leonard's infatuation with Penny may not be an epic love story à la Cheers' Sam and Diane, cocreator Chuck Lorre says, but "the infatuation will continue to build." Watch video clips | Photos | More Returning Favorites coverage