Marked Thought by Bob Mason
Two rows of five cards are dealt, face down. A spectator freely indicates any three cards, and a marker is placed on each selection.
One more card is dealt on each of the ten face down cards. When the pairs are turned face up only the three selected by the spectator are matching pairs.

Of course this can be played any way you see it ... the performer might want to display the matching hands as an open prediction or bet by placing the bets on 3 winning cards.
The spectator can have the choice to move those bet predictions if they wish ... but the performer always wins.

Easy to do. Using no gaffed cards or gimmicks.

Click here to view attached image.