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 peaceful snooze in 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.
For our money (not to mention caliber of friends), the Homer Simpson version is far more appropriate. Especially if we can figure out a way to hook it up to one of those remote-controlled water cannons.