It's not pretty, but it's bright.

Fun with LEDs. Five bright white LEDs and four AA batteries and I have myself a pretty decent flashlight. I just need to ruggedize the wiring and add a switch. There's definitely some spill that could be better used if I had reflectors around the LEDs, but it's pretty good anyway. They're rated to put most of their light within 15 degrees of the axis. Buying the parts from Digikey and building it myself is turning out to be cheaper and more satisfying that most of the bicycle or headlamp solutions I've seen, although mine isn't quite as tough and may be short a couple features.
( picture )