This is really a 2 spectator trick but can be done one to one. The magician asks spec1 to name any pair of cards. Let us say they named kings. The magician then pulls out the two kings and places them face up on the deck. He then counts them both off showing both clearly and places them face up on the table. Next he riffles down the deck asking spec2 to say stop anywhere. He does and has spec2 remember the card he stopped at. The card is then replaced and the deck is shuffled. Then the deck is spread face up and their card is missing! The magician then separates the two kings and there is a face down card between them! Everybody is going like, No way! as the cards are turned over and it is their 6 that is sandwiched between the kings! This is a superior trick!
This trick is suitable for intermediates.