This is so funny that it will boggle your mind and you will keep trying it as least 50 more times to see if you can outsmart you foot. But you can't!
1) While sitting at your desk, left your right foot off the floor and make clockwise circles with it.
2) Now, while doing this, draw the number "6" in the air with your right hand. Your foot will change direction!
I told you. And there is nothing you can do about it. Make sure you pass this on to your friends. They won't believe it either!