Pizza Box Solar Oven
And everyone has pizza boxes lying around. A good use of recycling them. And they’re the perfect size to make a pizza in. 
How does this help reduce using energy? Obviously, it eliminates the use of energy in an oven run by electricity or gas, but it also helps reduce energy usage in other parts of the home as well. Air conditioning on hot summer days is a massive energy drain, and those days are exactly when solar cooking could work, instead of heating your house with an oven only to cool it down again. Also, the oven is often placed right beside the fridge! The solar oven is an example of passive solar heating, which is using the energy of the sun to heat things up directly. Well designed houses can be heated by entirely passive solar, except during the darkest, coldest months of winter.
