Is This Your Card?

Effect: The magician lets an audience member select any card.
The audience member returns the card to the deck.
After examining the cards, the magician finds the audience member's card.

Begin by cutting the deck and having a spectator take the card face down.
Glance at the face up card that is on the bottom part of the top pile. If that confuses you, just know that it's the only card that you can actually see what it is. Remember what this card is. It will be your key card.
Have the specatator put the card back into the exact spot where it was. Place the top pile back on top of the spectator's card.
At this point, you have enough information to find the spectator's card by looking through the cards. You don't know what card they chose, but you do know what the card that is right behind it is. (Your key card)
Go through the deck, and when you see your key card, the card right above it is the spectator's card. From there you can reveal it in anyway you chose.