Sinclair's Eon Extreme claims to have the highest power-to-weight ratio of any flashlight in the world. Based on its tiny size and shining it in my face, I can say that this is most probably true.
The credit card-sized flashlight is rechargeable via microUSB, and fits nicely in a breast pocket. It's 50£ ($77) and comes next year. The production model will have a variable dimmer and a lanyard. They're also making a hands-free kit and a bike attachment for spelunkers and bikers, respectively. (Though there's no reason why you can't be both.) [Ian Sinclair]