Kaley Cuoco, who plays Penny on The Big Bang Theory organized a flash mob to take place during a live taping of the show. They did the flash mob choreographed song and dance to the ever popular song "Call Me Maybe" by Carly Rae Jepsen. Kaley said that her and her sister figured the whole thing out to seem like someone was pranking the cast, but then the cast joins in to prank the crew!