Gelaskin make a range of artistic and protective skins for iPods and phones, but they also make them for Mac laptops.
They're marketed as protective covers, and while they will protect your Mac from surface scratches they're really ways of adding a bit of flair and personality.
Each Gelaskin simply peels off its backing tab like a big sticker and secures itself to the lid of your Mac. They stick well enough and we didn't have any problems with it peeling off during our test. Neither do they damage the surface of your Mac, and can be easily removed if you want to change the look.
Coming in a range of exotic designs, such as Red Robot and Fuzin Raizin, these are skins for people who really want to think differently and throw Apple's measured, considered approach to design out of the window – and add some crazy colours and surrealist abstract art. If that sounds like you then Gelaskin could be just what you're looking for.