A very simple and impromputu card revelation can be done thus:
Take a flash pad or small piece of flash paper, and a pen, and hand them to the spectator.
Now, spread the deck in front of them face-down, ask them to select a card, look at it, and return it to the deck.
Control the card to the face of the deck, and tell them you want them to write the name of the card on the paper and fold it up. You then turn around, claiming you don't want to see what they've written.
While you are turned around, backpalm the selection.
Take care not to flash the backpalmed card (ensuring it is palmed so that upon production, it's FACE will be facing the audience—i.e. with its back agains the back of your hand.
Now... place the deck upon the table and take the piece of paper from the spectator. Pass it into the hand which is backpalming the card. and hold the paper high (in the 'backpalm production' pose

)
Now, take a lighter from your pocket, or borrow one. Set fire to the paper, and in a small upwards 'jolt' toss it an inch or two from your hand, whilst at the same time revealing the backpalmed card.
Voila!
Very strong. Especially if you have the card SIGNED as well.