One can make a really cool alcohol stove out of pop and beer cans. But one can make stoves and ovens that look much less elegant and burn fuel that is easier to scrounge from all sorts of materials. The best ideas can be found in places of great necessity: areas that are usually or temporarily without a lot of infrastructure. Take a look at news photos of disaster areas, refugee camps, and the middle of nowhere. Human ingenuity wins over adversity almost every time.