Martin's classic effect, still used by magicians everywhere, after 30 years.
This is in three phases. The first two are similar, but with variations in handling. The third phase has an unexpected "knock-out" finale.
In the first two phases three blank cards and an ace are shown. A blank is placed aside facedown, and the ace is put between the other two blanks. A spectator fails to find the ace because the three cards are shown one by one to be blank, and the ace is on the table.
The third time the spectator usually guesses that the ace is on the table. But it is shown to be really a blank card, and the cards in the hand are shown to be ALL ACES!