Fancy some beachside music? Be prepared by making your own waterproof stereo from a cooler, a car battery, and any car stereo or radio you can find.
Even more useful than its waterproof nature is the use of the car battery, meaning you won't need to be anywhere near a power source to use this — perfect for the beach, tailgating or pretty much anywhere outdoors. You can get most of the materials pretty easily online, and the sawing of holes and screwing on of water-tight bezels should be a piece of cake to any seasoned DIYer.
You may want to be at least a little comfortable working with electronics for this project though, as you'll need to wire up the speakers and the battery yourself. It shouldn't be too difficult a job — the instructions are quite detailed, and have accompanying pictures every step of the way. The only question now is where to put the beer when the cooler is full of electronics. Hit the link for the full how-to.