If you live in a cold climate and you're sick of paying to keep your food cool when it's already plenty cold outside, web site The Daily Green describes how to build your own Ambient Air Fridge to put that cold air to good use. The author uses everything from two-by-fours to computer fans to complete the project, which requires a bit of dedication to the cause, but if you're willing to put in the effort you'll be rewarded with an environmentally friendly, money-saving winter fridge.