Five cards are shown to the spectator with the request that he mentally selects one card.  Moving the cards about a bit, you finally remove one and place it in your pocket.  Spectator now reveals his choice and you remove that very card from your pocket, having apparently read his mind. 
 
But now come the "kicker"...the four remaining cards WHICH HAVE BEEN HELD IN FULL VIEW ALL THE TIME are slowly turned over and shown to the the FOUR ACES!