Originally Posted by
msgisme
My friend just got a set of lights installed on her fork and dropouts: they are powered by magnets on the spokes and flash twice for every revolution of the wheels. Nice bright LEDs, no batteries, always on, hard to steal. I am going to get some soon as well.
One brand is
Reelights and they work pretty well. As SixtyFiver mentioned, they're good for being seen but the headlight isn't bright enough to actually illuminate the road ahead even on very dark nights. There are also quite a few DIY tips and instructions on the net and YouTube of how to make your own using LEDs and hard drive magnets.