I saw that yesterday in my email. With the amount of water they used he'd be screeching to a stop 1/4 of the way down the slide. It is fun to watch though. Oh, I have no idea how they did it, smoke and mirrors I guess.
If you have ever done slip and slide you know its FAKE, two buckets of water aint getting but a few feet. much less any kind of momentum for that kind of launch.
I am waiting for the Darwin awards from the lemmings that try it though.