The Ultimate Penetration!
Show an empty card box with a slit in the middle. Insert a playing card through the slit to cut the box in half. Now, take a signed coin and place it on top of the box, closing the flap. The coin then penetrates the card with an audible sound and stops at the bottom of the box.


Can be done impromptu.
Practical and very exciting.
Fully assessable before and after.