One of the best places to play practical jokes is the pool. And here's a perfect way to make your friends jump out of their skin while trying to enjoy a peacefulin the sun.
Just when they're dozing off, float the submersible "RadioRaft" right next to them and blast 400 watts of sound from its five speakers--then sit back and enjoy. They'll forgive you after seeing the beer you have chilling in one of its six stainless steel cupholders, which sit adjacent to the waterproof storage compartment designed to hold an MP3 player.
That is, if you're willing to shell out $2,000 for it, as Slippery Brick says. Which is ridiculous considering how many other are available for a relative pittance.
For our money (not to mention caliber of friends), theversion is far more appropriate. Especially if we can figure out a way to hook it up to one of those remote-controlled .