A CLEAR glass is inverted over a plastic coaster. You pick up a coin and it penetrates the upside down glass and lands on the coaster. This is a visual appearance. The glass and tray are always visible. No sleight of hand. Use your own glass.
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