Tie 2 feet of fishing line or other thin, clear string around a button midway down your button-up shirt. Attach the other end of the string to the face side of a playing card. Put this card on the bottom of the stack and place the stack carefully in your pants or shirt pocket until you are ready for the trick.
Take out the deck of cards, which should be face-down, and hold them in your hand. In order to force the audience to pick the card that has the string attached, tell them you will begin shuffling the cards until a volunteer from the crowd tells you to stop.
Create an illusion of shuffling by holding the deck face-down in your right hand. Begin by slipping the first several cards off the top of the deck and transferring them to your left hand. The trick is to transfer them into the other hand as quickly as possible so that the speed and the motion of the cards make it appear that you are actually shuffling them.
Stop shuffling when you are told to stop by the volunteer. Turn over the deck in your right hand and show him the bottom card, which has not moved because you have been taking cards from the top of the stack.
Place the stack with the chosen card on top of the other stack you have created.
Turn the deck of cards in your left hand so that their faces are to the audience. Find the string and hold it over one of the fingers of your right hand. Lift your right hand, with fingers spread, slowly above the deck of cards until the chosen card slides out of the deck enough that it almost appears to be floating.
Hold the deck, with the chosen card still sticking out, and show it to audience members, who will confirm that the floating card was the card chosen.