http://www.wired.com/gadgetlab/2011/02/water-powered-jet-pack-runs-for-two-hours-on-a-single-tank/
http://www.youtube.com/watch?v=CiUNe5908FA
Interesting....
Had seen this a while back on some website.. Would be nice for a ride but will probably get boring after a while.. They want to use it for ship maintenance n stuff.. Wonder what will happen if the jet of water hits his leg?
What happens to metal in a water jet cutter >:D