Dark Card trick
"Jean Boucher's Dark Card Trick This one is a dynamite fooler! EFFECT: A card is choosen from a red-backed deck and signed across the face, then returned to the pack. The magician snaps his fingers over the deck, whereupon it is spread, showing one blue-backed card clearly visible in the center! The card is removed and turned face-up, showing it to be the signed selection! Remember, the card is handled by the spectator both before and after the change, and can even be left as a souvenir! Use your own deck plus a "special something". Comes with booklet by Gary Ouellet, and more ideas from Bob Parmer and Phil Matlin."
Camirand Academy of Magic