MMST 2000 trick
"BrumoliMental Magic Swindler Test 2000(MMST)EFFECT: A spectator thinks of any day significant to him, like a birthday or wedding anniversary, etc. He looks up this day in a beautiful multi-colored calendar book which has a different playing card next to each day of the year with a green or blue border around it. The performer has his back turned the entire time and cannot see the page the spectator is looking at. The performer instructs the spectator to call out the colors of the borders of the 7 cards in the column in which his card resides. However, when the spectator reaches his card he is to swindle and call out the wrong color. Nevertheless, the performer knows the identity of the card and can make use of this however he sees fit!"
Brumoli
