Nick Trost's Classic Packet Tricks - Mississippi Monte

The “Old Sucker Game” with new, surprising twists! Four cards—one
an Ace—are shown, turned face down and a spectator tries to paper-clip
the Ace—but fails! One odd card is discarded but again the spectator can't
clip the Ace! Finally the cards are fanned out wide and the spectator clips
the back of a card. The other two cards are shown so now he’s sure he’s
clipped the Ace. The clipped card is shown but the ACE HAS VANISHED! The card
laid aside is turned up—it's the missing Ace!