Originally published as "The World's Greatest Invention" in Approaching Magic, it's not a card trick, and not a coin trick. It's baffling, amusing, and astonishing. It can be performed for a room filled with sophisticated adults or at a kid show.
On top of that, the method is one you will love.
Imagine handing one spectator a glass of beer (or any beverage), and another a simple straw mat. You take back the glass of beer, hide it behind the mat for a moment... and it vanishes.
You show both sides of the mat - the glass of beer is simply not there. Then you reach behind the mat and produce the glass, still filled with liquid.
You repeat the vanish twice more, escalating the impossibility and further confounding the audience. You shake the mat - no glass, no beer. You turn the mat sideways, roll it into a tube... and reproduce the glass of beer to a guaranteed ovation.
The glass is not gimmicked (use you own glass), nor is the liquid or the mat... but there is a gimmick and it has been beautifully realized.