How to do this
1. get a cup
2. put a penny inside cup
3. fold cup so it looks like cup at 00:14
4. hold open end between fingers, with closed end pointing away from you.
5. when cup is swung, the penny hits the closed end of the cup making it sound like you are hitting a penny out of the air. The penny in the cup then falls back to the other end of the cup and when swatted again, cup makes sound again.