There's a great trick in the Book "Ah-Ha!" by David Harkey & Eric Anderson, called "OutSmart". In this routine, you ask the person for the name of their very favorite playing card. Once they've named it, you spell a phrase about their favorite card, and the spelling finsihes right on the named card!

Unfortunately, as it's written, there is a certain something with which you can be caught, that gives the trick away. Fortunately, this certain something can be eliminated by using memory work. Getting rid of the special something makes the trick more open, and makes you feel less guilty.

I've been doing OutSmart this way since about 6 months after the book was first released. If you like applause, don't do the trick this way. The response is most often stunned silence.