This gimmick will produce a loud crushing sound as if you have cracked your (or someone's) neck. Just walk up to someone with your neck tilted to one side and wait till they ask you if there is something wrong with your neck or you tell the person you are
A fake $100 is attached to the end of the line. Drop it on the floor and wait for someone to pick it up. Let go of the button and it automatically returns to your hand while the victim is left without the money!