I doubt there is anyone left that hasn’t had to use their cellphone as a flashlight at some point or another. The bad thing about using your cellphone for that is that most of them the screen darkens after a short time. Plus it’s not exactly built to be a flashlight, so the light is a bit unfocused and doesn’t illuminate a whole lot. Thankfully, Think Geek has a very tiny flashlight that won’t require you to replace batteries, plus it’s incredibly portable.
I’m not a fan of bulky keychains, but this one seems to be small enough to make it easy to carry around. Thanks to the attached keychain you could just attach it to your keys and always have it handy. The big feature with this tiny LED flashlight is the very small hand crank. You can purchase it for all of $4.99 through Think Geek.