Have any old film canisters lying around? You can give them new life by turning them into torches.
The electronics in this build are nothing surprising, but it's a very tidy implementation. You wire up a battery to an LED bulb through a switch, mount the switch to the side of the canister, and poke the light out through the lid.
This build is so cheap and simple that you could easily build a bunch and store them in various drawers around your house. They're fun to make and a great use of what might otherwise go to waste.
Film Canister Flashlight [Instructables]