Write an article based on this "Have your friend select a card from the deck. Ask him to show it to someone else watching. Hold the deck out and ask him to slide the card anywhere back into the deck. Put the deck behind your back, turn back over the top card and flip the deck around. Tap the deck with your middle finger and finger through the deck while looking at the back of the cards."
He should then take the card and look at it, memorizing what it is. Tell him he should keep an eye on his card at all times. When it's in his hands, when it's in your hands his eyes should always be on it. While he does this, turn the deck over and flip over the top card so that it appears as if the deck hasn't been tampered with. So, say you're holding the deck with the backs facing you. You then turn it over so the faces are facing you, flip over the top card so it's the back again, and get away with it looking like the backs are still facing you. Tell him to think very carefully about where to place the card. He doesn't want to mess it up, does he? Alternatively, if you're pretty good, you can clasp the deck in your hands (so your friend can't see what side of the deck is showing), take up the top card, and ask him if that's his card. Then you say, "Just kidding!" and return it to the deck facing the right direction. You know what this means, right? When the card is returned facing the right direction, all of a sudden the only card in the deck that's not facing the right direction is your friend's chosen card. Scan through until you find his card (flipped over) and he'll be amazed. Make a show of it. You could tap the deck, say a magic word, have your friend blow on the deck, whatever. Do something that allows the magic to occur. Once the process has been completed, slowly fan through the deck, letting the suspense build and build until your awesomeness comes to light.