The same guy with the floating cup does an even simpler trick to amaze and amuse fast-food people:
I particularly liked one employee's reaction to his claim to be from another planet. The young lady is not the least bit fazed by this and simply asks, conversationally, which one.
[Updated: I previously managed to spell "fazed" as "phased," which at least I managed to catch myself, eventually... The latter expression would be valid only in an enemy damage assessment on Star Trek, as in, "It doesn't seem to have phased them, Captain."]