The surname of Sheldon and his family: George Sr., Mary, George Jr. and Missy.
Season 1, Episode 9 - The Cooper-Hofstadter Polarization
Aired March 17, 2008
When Sheldon and Leonard are asked to present their work at a physics conference, Sheldon unilaterally decides not to. Leonard and Sheldon feud when Leonard decides to present their work alone in spite of Sheldon's objections. Penny's attempts at reconciling the pair only make matters worse.
Season 2, Episode 6 - The Cooper-Nowitzki Theorem
Aired November 3, 2008
When a young grad student, Ramona Nowitzki, falls for Sheldon, the whole gang is confused - nobody more so than Sheldon. Though Sheldon is initially pleased to be the subject of someone's adoration, he is soon searching for a way out of their "relationship".
Season 6, Episode 14 - The Cooper/Kripke Inversion
Aired January 31, 2013
When Sheldon is forced to work with Barry Kripke, he is surprised to find his work is not at the same level as Barry's. Meanwhile, Howard and Raj spend $1,000 on action figures that of themselves, landing Howard in trouble with Bernadette.
Season 7, Episode 11 - The Cooper Extraction
Aired December 12, 2013
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 lifes he has become.