flowerbug
Sustainability Master
if you already have a computer UPS (a battery pack which allows you to run the computer for some period of time when the power fluctuates or goes down) you already have a battery that you can plug a LED light into which should last a good long time (the lamp i have here is all of 8watts so that's a very tiny amount of drain on a bigger battery pack) - it will light up the whole room easily enough.