there are night lights on in friends' rooms. constantly on. a slow, steady, painful trickle of energy leak from each one.
so a buddy and i went down to the lab and cultured everyone a couple plates of luciferase bacteria!
this means they glow in the dark as they metabolize. the bacteria use quorum sensing to activate their little glow enzymes, so when a big enough cluster of them grow emerge... bling!
they aren't that bright, more like a faint smear of stars across the culture plate. but a big plate gets a decent enough glow on and its so nifty no one uses their night lights anymore :)
(disclaimer: all bacteria were rigorously tested for for nasty side effects through the scientifically sounds technique of smearing them on the back of my hand. hey, it's my lab, no one tells me how to do science)