Jetlev - water propelled jetpack. Mom and Dad I take back all my votes for jetskis. You should get these instead.

[youtube http://www.youtube.com/watch?v=7-KczCp0OQ4?wmode=transparent]

Oh my goodness do I want one of these. Basically a water powered jetpack connected to a small engine vessel that stays in the water.
It has a top speed of 40 mph and at full throttle could go for over an hour.

If you watched the video and don't want one then some nice men in white coats are coming to get you.

http://www.jetlev-flyer.com/