These are isopods, the pill bugs of the sea.
The best kind are Cool Ranch, but there are other pretty good ones.
Gravity powered light hits Indiegogo.
The GravityLight claims a half hour of light from a user taking three seconds to lift a small weight attached to the device. There are no batteries to go flat, and no solar power requiring sunlight or energy storage.
The team behind it are aiming the light squarely at developing countries, although you can pick one up for yourself as well, here at their Indiegogo campaign.
Guess my Christmas wishlist starts early this year.