A Lie Detector in a Card Case
Your participant shuffles and spreads the deck face down then slides out one card for himself.
He divides the deck into two piles and buries his card in either half, then squares the packet.
The half-deck is dropped back into the card case. One card at a time is removed (while the performer's head is turned) and shown to the participant for a remark about that card.
He may lie or tell the truth, his choice...
Each time, the performer determines the Veracity of what the participant said - and spots the lie each and every time!
After one card gets a 'different sort of reaction' the performer not only identifies it as the one chosen previously but also manages to determine it's value and suit using the same method.