You have to watch the faces of the audience when you perform this trick. And that's not surprising, because it's actually quite an astonishing thing. Here's what happens:

You place a playing card and any piece of paper on a crystal-clear 13.5 x 13.5 cm plastic plate, cover it with a second identical disc, and enclose the whole thing with four rubber bands. Now you push the top disc with your index finger, and instantly the card breaks through the bottom disc, while the piece of paper remains trapped!