Solar cooking gear is a handy science fair project, and also a useful survival skill for camping. It also can be fun to construct a solar cooker just to see the power of the sun at work. It is entirely possible to make a good solar cooker out of a shoebox or any other box with a lid that can be easily removed.
Remove the lid from the shoebox, and cut out a rectangular flap from the inside of the lid; try to leave about an inch of cardboard around the rectangular hole. Leave the rectangular flap attached.
Cut a piece of cling film and lay it over the hole on the inside of the lid. Glue it firmly to the bottom of the shoebox lid.
Glue sheets of aluminium foil to the inside bottom of the shoebox. You will want to make sure that the shiny (reflective) side of the aluminium foil is up because you want a bright reflector there. Do the same to the inside of the rectangular flap in the lid.
Tape black construction paper, or use black paint, to colour the outside of the shoebox. You want to make it as dark as possible; the darker the colour, the more infrared energy the cooker will collect from the sun, and the faster your food will cook.
It will take a fair bit of time to cook something in your solar cooker; on a very hot, sunny day, you can expect hot dogs to cook in about 20 minutes, and it will vary depending on cloud cover and what you're cooking. You'll want to position it (ideally on a dark surface) so that the flap cut into the lid of the box directs sunlight into the cooking chamber.