red was a username I came up with because its what best represents me. It's my favorite color, my favorite movie, my username for countless other things, and it just sorta belongs. 303, however, is a random number with no significance.
Uh, I believe it was world of warcraft. A few years ago, a friend was showing me an ironforge glitch, and the character she made for it was named Faily. Liked the name, started using it.