We have seen plenty of small flashlights in the past. The MBI MatchBook is quite interesting though. It comes with 8 tiny flashlights, each the size of a match. These are waterproof and fully submersible. They are so small, you can fit a bunch of them in your pocket. Each flashlight lasts for up to 8 hours on its lithium tube type battery.
This flashlights are available in a variety of colors. You can find out more on Indiegogo.