The method I use can be found in an Edward Norton movie. No, I won't say which one, though some of you have probably already guessed. If you haven't, you need to watch more movies. Method works very well for me. No gimmicks, no setup, very easy to do, but requires you to have a certain amount of tact and performance ability to really sell it. It's not 100%, but in real mentalism you never want to be 100% anyway.