Total Console is selling a ii case Crystal Chameleon case for the Nintendo Wii
This thing is made out of plastic and replaces the Wii case, so you'll need to do some disassembling (and void your warranty) to install this thing.
The special thing about the Crystal Chameleon Wii case is that it has a build-in thermometer. A small LCD display shows the temperature and the LEDs inside the case change colour every time your Wii gets 5° hotter.
Every time the Wii gets 5° hotter, its LED lights' color changes to a hotter hue on the color spectrum. By the time it's up to 55°C, it'll be glowing red as a beet.