Arrange the cards in the deck so the cards are in pairs that add up to 13, and the odd numbers are all on one side and the evens on the other. Place hearts with spades and the diamonds with clubs. Cover up the end of the deck with a joker card so the deck appears to be legitimate.
Lay a regular deck in front of the participant and have him shuffle the cards and pick out a card in the deck and tell you what it is.
Tell him that you will transport that card into a second deck of cards that is in its box, right in front of you.
Open the invisible deck and remove the cards from their box. Begin fanning the cards out in front of the participant, placing pressure on the cards so they stick together as you fan them out. Because of the arrangement of the cards you will know exactly what card matches up with the card your participant has picked.
Look for the card that goes along with the card your participant picked. So for example, if he picked the 10 of hearts, you are looking for the 3 of spades to make up 13.
Fan out the cards until you see the pair turn up in the deck. When you see the pair, ease up on the pressure to let the upside-down card slide out from underneath. It will appear as though it is the only upside-down card in the deck.
Turn it over to reveal the card your participant chose.