fan out the cards
have your friend pick any card
tell him to memorize it. if you want have him to put it on his nose and say: ego sum stolidus vos es veneficus
split the deck in half, which means within two cards of the 27th card, or else the trick won't work, but don't sit there counting them out.
tell him to put his card on one of the piles. put the the other pile on top of this one.
lay out cards into four piles
ask him if he sees his card in any of the piles, and discard all but the one containing his card
lay into four piles again
discard pile which extra card lands on
take top and bottom card off of each of the three piles and discard them
stack the cards
take the top and bottom cards off and discard them
flip over the last card.
should be your friend's