I'm sure this project has been done many times in many forms, but I just wanted to add my project to the list. As I was throwing out my clutter, I found one panel of an old, fiberglass tv satellite that I hadn't thrown out yet and I was also throwing out a bunch of junk CD's. This is when the idea came to me to make solar ray gun. I didn't want to spend/waste alot of time, so I didn't cut the cd's into smaller circles -- I just hot glued the cd's directly to the surface of the satellite panel. Since the panel is curved (parabolic?) and the cd's are flat, but flexible, the cd's will somewhat conform to the curve of the curved panel and focus the solar beam into a smaller pattern. For this particular panel, I was able to get a piece of wood to start smoking, about 3 feet in front of the panel and the beam focused down to about a 3 inch diameter pattern.