How to Glow in the Dark?

i remember wondering about how light travels and why things ar various colors, and how that all works. Almost everything in the universe glows in some way or another. There's a lot of really subtle physics going on about how things absorb light when they decide to give it off. I like to take things apart and think about a single particle interacting with one other particle. i've utmost respect for chemists and biologists who can think about such complex systems.