Run through a deck of cards, pulling out all the cards that have an "asymmetrical orientation"... That is, cards whose faces have a "right side up" and an "upside down". As you do this, explain that you're looking for the "psychic" cards in the deck.

Next, have your volunteer pick any card from your small pack of "psychic cards." While he's examining his card, turn your deck around and allow him to return his card.