From the MAKE Flickr pool:
Flickr user P^2 – Paul created this fridge controller run by a Teensy:
This is a microcontroller-powered temperature controller for a fridge I built out of fabricated necessity and spare parts last weekend.
Backstory: We replaced our ancient 2nd fridge with a big new upright freezer, which left our little chest freezer empty. Sometimes we do need the extra fridge space though during harvest season at the farm, so I figured I could just turn the temperature up on that old chest freezer and turn it into a fridge. Nope. Highest it goes is -4C.