Frightening Spike by Premium Magic
A "Russian Roulette" theme, the props consist of 3 wooden blocks. One with a sharp spike embedded in it. A spectator is invited to cover the 3 blocks with 3 paper cups and mix them. It is impossible to tell which cup has the spike under it. You then dramatically bring your hands down on two of the cups, crushing them. The one with the spike is left untouched.