On Sheldon (Jim Parsons) and Amy's (Mayim Bialik) date night, she comes up with an experiment in hopes to speed up Sheldon's romantic feelings for her. Her experiment includes many of his favorite things like The Super Mario Bros. music, Strawberry Quik, and spaghetti with cut up hotdogs. Meanwhile, Leonard (Johnny Galecki) accidentally asks Penny (Kaley Cuoco) to marry him during sex. Watch The Big Bang Theory on TBS. #TBS #TheBigBangTheory #JimParsons #MayimBialik #JohnnyGalecki #KaleyCuoco SUBSCRIBE: bit.ly/TBSSub Download the TBS App: bit.ly/1qBbkMW About The Big Bang Theory: Leonard and Sheldon are brilliant physicists, the kind of ''beautiful minds'' that understand how the universe works. But none of that genius helps them interact with people, especially women. All this begins to change when a free-spirited beauty named Penny moves in next door. Starring Johnny Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, Kunal Nayyar, Mayim Bialik, and Melissa Rauch. Cr...