Things You Didn't Know About The Big Bang Theory

3)

The cast really is musically inclined. Bialik learned how to play the harp after it was decided that it was Amy's instrument of choice;

Parsons (Sheldon) learned how to play the theremin, so when scenes call for them to play, they actually are. As for their skill levels, Parsons joked his inability brought him to tears.

For his part, Galecki (Leonard) also plays the piano.

Chimed in Cuoco, "And when Penny drinks, she's really drinking!"