I've told people about this method I use, and finally decided to make a quick vid with my phone. Check it out. It'll get your muscles burning like crazy, and do it super fast! If you use all your fingers (pinky especially!) to rotate the paper in your hands to crumple into a ball, you'll feel a burn like you wouldn't believe! Try it.
*edit* didn't know if your user board supported embed code or not. ha!