Well, when I was a stupid kid in high school (this is 10 or 11 years ago), my friend and I were trying to figure out what we wanted our hacker screen names to be, the idea was we were both going to choose a famous assassin from history, then add 2600 on the end (a quarterly magazine dedicated to hacking).
Well, our grand plans of "hacking the planet" (

) never came to fruition, but the screen name stuck and I've used it ever since