This is one of Lennart Green's favorite effects. You show the audience a special deck of cards. Every card has a different back. You tell the spectators that each card was stolen from a different poker game, a souvenir of a winning night.
You take two of the cards and place them face-down on the table. The spectator chooses two more cards. The first surprise is that the two chosen cards match your predictions. The second surprise is that not only do the faces match, so do the backs. The third surprise is a real kicker. Every other card in the deck is identical except for the two cards chosen by the spectator. The Stolen Cards comes with a special deck and is completely self-working.