When I was in college and had too much free time, I used to be involved in an online freeform RPG. The focus was more on the writing itself, though; the way it worked was one person would write a chapter of a story, and then someone else would write the next chapter, then someone else, and then someone else. Coupled with the whole stigma of RPG players being losers with no lives (though most of us involved tended to fit that description anyway) we tended to call it "Collaborative Fiction" instead.
But it largely really was just role-playing. Most people had one character that was their representation in the story; usually it was a character which shared the same name as their online handle, and in some cases their own personal identity.
The stories themselves were comic-book influenced, so the characters the people wrote were superheroes. We'd fight supervillains and stuff. My character was, creatively enough, a cyborg guy with a gun who ran around shooting stuff.
Okay, it borrowed very liberally from the Marathon Marine. At first, anyway... over time it sort of evolved into a 25th Century Western Hero or something -- basically, by the time I'd finally gotten bored with this, all that was left was the cyborg part and the shooting stuff part. Something about nobody else finding Marathon as profound as I did. Usually my character would just show up, shoot stuff, and then disappear for the rest of the story.
So anyway. One of the things that bothered me about this whole thing was the way some authors couldn't tell the difference between a collaborative fiction story and self-indulgent power fantasy. What happened often was that some authors would hijack entire stories to make it all about them... like, "Captain Marmalade Saves Everyone, Part III." Or maybe they'd dedicate an entire chapter to wallow in angst and self-pity about their parents hating them. Or something stupid like that.
We called stuff like that "Kewl". The defintion was supposed to be ironic -- cool to people who write the stuff, thinking they're Tolstoy or Hemingway, and very much not so to people who just don't give a shit. Someone who is kewl is someone who thinks he's All That and just... isn't. Not necessarily because he's a bad person, but because no one cares. Writing "cool" with a "k" is kewl. A incorrect definition for a incorrectly spelled word.
Writing stuff like that ISN'T stupid, really. You have issues, writing about them is one way to deal with them. Fine. But dammit, that wasn't the reason why I liked doing the stuff. Reading about people's issues isn't FUN. I wanted to write cool stories about superheroes beating up supervillans and stuff. And explosions.
As time progressed, it got worse and worse... and it bugged me more and more. Until one day I decided I'd had enough and resolved to make a contribution to the story that was a parody of the worst of what I'd seen. Something so stupid and more obnoxiously self-indulgent than had ever been seen before. I would outkewl the kewlest.
And thus Captain Kewl was born.
Fast foreward maybe two years or so. I get Unreal Tournament. I open up the Player Preferences window and see that it has the option to put in a player name. I can't think of anything clever, so I put in "Captain Kewl".
I still haven't thought of anything more clever, so I've pretty much stuck with it.