I haven't used this yet, but I think this would fry:
Use a blank face deck. Hand it to the spectator and have them "inspect" it, making sure it's normal. Tell him/her to pick any card they want (while looking through the "faces"). Ask him/her what the card was and let them shuffle to lose it in the blank-faced deck. Then, take the deck back, show the faces blank and the backs normal, then do a simple erdnase to "print" their card. Oh man this sounds sweet just typing about it... You can show the rest of the deck completely blank on the face.