Christmas Episodes on "The Big Bang Theory"

Season 2, episode 11: Leonard is disappointed when Penny develops an interest in an attractive physicist at the university. Meanwhile, Sheldon struggles to find an appropriate Christmas gift for Penny.

Season 3, episode 11: Leonard's mother, Dr. Beverly Hofstadter, is in town over the Christmas holiday. His mother's visit is distressing for Leonard, especially after she finds out about his relationship with Penny.

Season 6, episode 11: Sheldon is haunted by the memories of Christmas past when the guys play a festive game of Dungeons and Dragons. Elsewhere, Amy, Penny and Bernadette try find a girl for Raj when he joins them on ladies' night.

Season 7, episode 11: When Sheldon flies back to Texas for his sister's childbirth, the gang gather to decorate the apartment's Christmas tree. When they begin to wonder what life would be like without Sheldon, they come to realize how big a part of their lives he has become.

Season 8, episode 11: Amy hosts a traditional Victorian Christmas Eve dinner as Raj's father comes to visit. Sheldon goes with Bernadette to find the perfect gift for Amy, while Leonard, Howard and Raj try to shoo out a bird they let into the university clean room.

Season 10, episode 12: After spending the holidays apart, the gang get together to hear about Sheldon's and Amy's trip to Texas, Leonard's and Penny's Christmas tree adventure, and Howard's and Bernadette's first days as parents.