Unroll a small piece of double-sided tape and stick it to the bottom of your finger. Cut it large enough to make a card stick to the ceiling, but small enough to conceal from spectators. Do this out of the sight of anyone who will witness the trick.
Ask for a volunteer from the crowd. It does not matter who you recruit to do this trick, because unlike more complicated tricks, the age and size of the volunteer has no effect on the outcome.
Have the volunteer pick a card out of the deck at random. Hand the volunteer a pen and ask him to autograph the card. It doesn't matter whether you see the card's suit or number. Ask the volunteer to give you the card.
Use a simple magician's reshuffling trick to get the volunteer's card to the bottom of the deck. While you announce the next step in your trick, gently apply the tape to the bottom card and make sure it peels off your finger.
Throw the entire deck of cards at the ceiling hard, keeping them flat with the surface. If the trick is performed correctly, the autographed card will smack the ceiling first and stick while the others fall. Peel the card off the ceiling, indiscreetly remove the tape and show the crowd the autographed card.