This maybe one of the best mindgames i've ever seen link do, whether you guys try it or not it up to you. I'm not to sure how pratical it is but could be useful.
http://www.youtube.com/watch?v=WAPLQzUR1HA
Epic Mindgames
http://www.youtube.com/watch?v=WAPLQzUR1HA
Epic Mindgames