Someone in the street performed this trick to me last week, and i've come across someone else doing it on youtube. I'm uncertain how it's done and i found it very good and think it's a brilliant trick, the elastic band has got me thinking and obviously when he hands him the card something has already been pre-set. But i can't work out how the rest is done, it could be something so simple and i'll kick myself, I'm still newish to magic and I'm not the worlds greatest, so if it is something simple i apologise! haha

Obviously we don't reveal on the board how things are done, but a PM would be nice! I love this trick and i need to know how it's done!
thanks

5 minutes 54 seconds onwards...
http://www.youtube.com/watch?v=D3akJddJ1ZU&list=UUk0Jv6cPuZ_jlRYkbTfQg6Q&index=2&feature=plcp