A few months ago, the power in my town went out. It was getting dark and I had no flashlights around. Fortunately, I had some super bright LEDs in my workshop. I came up with a quick and easy way to use them for a makeshift flashlight. For the rest of the night, I was able to read and navigate the house using these helpful lights.
Step 1: How to Make It
Find an LED (preferably a super bright white one), duct tape, two AA batteries, and a scrap of aluminum foil (or other conductor).
Stick the piece of foil onto a long piece of duct tape. Place the two batteries on the foil. One should touch the foil with its negative terminal, the other with its positive terminal. Now place the LED across the other two battery terminals, and wrap the remaining tape around the batteries and LED leads. Make sure to leave some slack so that the LED leads are not completely in contact with the battery terminals.
Step 2: Operation
To turn the light on, simply squeeze the top and bottom, bringing the LED leads in contact with the battery terminals. It may take some fiddling around with, but you should be able to turn it on by lightly squeezing the light, and turn it off by releasing it.
Its not pretty, but it certainly works well if you're in a pickle.