Now I've certainly done my share of DIY projects but while I find this one interesting, I won't be building it any time soon. The guy who did this put a lot of work into making the light and making a nice webpage detailing the construction. You can see it here:
But really if you value your time at all, there are lots of LED headlamps, flashlights and bikelights that fall into the sub-$20 pricepoint of this project. So why am I posting this here? Well, it is kind of nifty. And I'm thinking maybe you clever folks in the blogosphere will add a bunch of neat comments with links to your own home-brew lights and/or great bargain bike lights you've discovered.
Keep 'em rolling,