The Elmsley Count
The Effect
The magician has a stack of four cards and begins to place the top card on the bottom, one card at a time.
It appears as though the magician showed each of the four cards, but the third card is never seen.
How It's Done
Hold four cards in your left hand, have the second to bottom card be turned face up, the rest face down.
With your left thumb, push the top card into your right hand and say "one".
Next you use your left thumb to push two cards off of the three card stack in your left hand, pinching the cards together from the very left side as you slide them over so that the spectator cannot see that it is two cards.
As you begin to push these two cards away, put the card from your right hand onto the bottom of the stack.
As you grab the stack of two (appearing as one) with your right hand, say "two". Put the two cards on the bottom of the left hand stack.
Finally just take the next two cards off the top of the deck on to the bottom, no sleight needed, and say "three, four".
If you did everything correctly, the face up card will never be visible, so the spectator would think that all the cards are face down.