Big Bang Theory Keep Calm Bazinga Baby Tee The perfect t shirt to wear when you play a prank on your friends, the Big Bang Theory baby tee features a twist on Dr. Sheldon Cooper?s favorite catchphrase, Bazinga! The Big Bang Theory Keep Calm Bazinga Baby Tee is a soft, babydoll style girls? t shirt that leads off with the international symbol for the atom, which represents three electrons orbiting around a nucleus: Nothing says ?Sheldon? like a bunch of flying atomic particles. The phrase ?Keep Calm and Bazinga!? is shown with white letters on a bright red background..