pond hockey - no zamboni

"There is a huge amount of energy - a really huge amount - bound up in every material thing. You may not feel outstandingly robust, but if you are an average sized adult you will contain within your modest frame no less than 7 x 10 (to the eighteenth power) joules of potential energy - enough to explode with the force of thirty very large hydrogen bombs, assuming you knew how to liberate it and really wished to make a point."

Bill Bryson