sounds like a great idea to me. whoever suggested the submerging the pump was on the right track. A slightly "less cool" thing to do might be to pull the seat tube and fill his frame with water. I'm guessing the reaction to that might be a big stronger.

Here's another fun one. Do you have an old cassette? file the nubs off the middle gears (say 16-ish) and then swap it out for his. He'll be spinning along, shift and then be putting NO POWER to the wheels (this may hurt the freehub body though). just throwing ideas out of the top off my head

asbestos suit on.