ZERO GRAVITY really is the ideal opening effect- you walk up to a group and suspend a deck of cards, borrowed wallet, borrowed cell phone, pretty much ANY SMALL OBJECT on the very end of a folded dollar bill (the visual is insane) and then you immediately hand everything out -and your hands are EMPTY.
You can even BORROW the bill! The same effect can also be done with a folded paper napkin, a take-out menu, whatever.