Would you like to experience a brain cramp? No? Perhaps you'd like to give one to someone else?
Here is your chance! Watch this clip and see if you can figure out how this was accomplished. There is no slight of hand (palming) or trick photography.
If you are like me, you will want to review this and try to figure it out on your own. To not ruin that for you but not leave you hanging and very frustrated, here is a link that will explain what happened: http://www.youtube.com/watch?v=Rzzct1We-38
I need to go massage the cramp from my brain. How about you?