I made a thread like this once... And my one only had less than a page.
Ok, moving on,
I came up with my user name because at the time I joined, I had been playing through Rayman (the first one) and I didn't know what the little blue guys were named, so I just called them gretins for some reason. Then I randomly decided to use Gretin as my user name, and... that's about it.
Just like how I randomly decided to post in the thread...
(By the way, I eventually learned that the name was antitoon)