Homemade 5 gallon bucket Air Conditioner: Small fan set on top of lid, 1 gallon milk jug of frozen water inside the bucket. Air output varies between degrees F. It can also be made with a styrofoam cooler instead of the bucket.
5 Gallon Bucket Swamp Cooler DIY Project - Cooling your tent or van. An evaporative cooler will reduce the temperature by 20 to 30 degrees. All the ideas that people came up with on this thread are a perfect example of radical self relience!