When I was a freshman in college, I drove from Walla Walla up to Olympia, WA to spend the weekend with some friends. I was the first to arrive and I didn't actually know the people who lived in the house particularly well, so it was slightly awkward for the first hour or so. One thing that I found fascinating was that in their kitchen, on the floor next to the rickety table, was a large wooden box with a big sun painted on it. While I was sitting there, making uncomfortable small talk, I watched as Aaron, the one person I did know, made a pot of soup. He sauteed veggies, added some beans that had been soaking and poured in a kettleful of water. As it came to a boil, moved that sun-painted box outside and opened it up. It was lined with tin foil and there was a piece of glass sitting on top. He came back, got the pot and put it in the box, securing the piece of glass on top. The expression on my face must have communication my curious and confusion, because before I could even ask, he started to explain that it was a solar cooker.
We ate that soup for dinner later than night and it was delicious and fully cooked. That was my initial exposure to solar cooking and while the concept has crossed my path on other occasions, I haven't gotten much opportunity to try to it out. However, this post on the Ethicurean has re-whetted my interest. If you are curious, you should check how Marc went about building his solar cooker. I'm now waiting with interest for his next post, which will detail what he made and how it turned out.
Picture link
It's definitely on the Neanderthal end of the cooking spectrum. It was developed
entirely by accident, when George Germon, of Al Forno in Providence, R.I., dropped a steak on the fire
without realizing it. 
