Make Your Own Solar Oven

And while we're talking about homemade solar, here are instructions from Alt. Build Blog for making your own solar oven mostly from stuff laying around the house. They recorded temperature up to 325 degrees, but mostly it stayed in the 200 to 250 degree range. Not enough to boil water, but you could slow cook a chicken.

Here's a link to the original source they used form Backwoods Home Magazine.