I've wrecked 2 mp3 players already (a Sansa clip & a Sansa m260) riding in the rain. Has anybody had any luck with specific brands that can handle rain, or that come with a good waterproof case?

Smaller is better (I strap my mp3 player to my helmet), and I'd prefer one that uses a AAA battery.

Or is there some easy way to make a waterproof case with some kind of rubber compound or something?

Any other ideas?