possible use cases --

all kind of wierdos

it will serve the same purpose as inverters or rechargable lamps do , they turn up automagicaly when power goes out . the n900 with kickstand open and light sensor detecting ambenient light can serve the same feature somewhat well

it would be fun at a party holding the n900 with a pint of beer automatic stroboscopic effect even better if sound monitering would have been there real flashy equlizeric effect

mounting it in a bycicle mount at night fun showing off specialy when street lights are 80mts apart

best of all convincing you its fun