I don't use Internet pseudonyms ... so, yeah. It's just Jack.

Vannevar Morgan, the protagonist of "The Fountains of Paradise" by Arthur C. Clarke. Dude uses his brain and sheer willpower to build a tower to the STARS.

I stole my nickname, Bumblor, from a friend because I was a bigger clutz, or bumbler, then him. The title has been stolen from me as well by another friend. The full title is Lord Bumblor, Upturner of Furniture and Breaker of Fragile Objects

Mine comes from my Freshman year at college. My given name is Mark, but there were several in my group of friends with the first name "Mark," so we were given nicknames. I was "renamed" Seth, another was Hobo-Mark, and a third Stinky... I made out best, I'd say.

It later evolved when I was running a D&D campaign. One of the players is a fan of the webcomic series Goblins, and he took it upon himself to worship the DM (me) as his in-character deity, dubbing me "The Great SethoMarkus." (Un)fortunately, it stuck. Now whenever I run a game with that group, I'm personified into the deity SethoMarkus...

I don't think I have to introduce my namesake so I'll just skip that part.

I've been using this nick for going on fifteen years now on many forums, gaming and otherwise. Frankly I'm shocked at how easy it was to acquire the name for my use...

Cthulhu, I just have to say that I love your profile pic. Every time I see it I get the mental image of Captain Deudermont fighting Cthuhlu...

I'll lay a bet on Cthulhu in that fight! Unless Drizzt intervenes then all bets are off....

Hircine is my favorite Daedric Prince from the Elder Scrolls.

I was in I think third grade... and my mother and I were trying to come up with my first username ever because I wanted to play neopets and children are asked to consult their parents by the game syntax and whatnot, so her and I are going through the process of signing up and per-usual all of the awesome and badass names my childish brain could invent were taken, such as Flame or Blade so the recommended names come up and those suck, so my mom asks to name two things I like and I'm all like, well I like jets, and I'm a nerd... and I like cheese, and fire, and so we start combining things I like and Firenerd and pyronerd and nerdfire are all taken so I end up with Jetnerd, and it has stuck ever since.

tl:dr Neopets wanted a name, good ones were taken, mum recommended it.

Emily the Strange books. Did not enjoy them that much and I liked the name even if my mind has actively gotten rid of any bad thing associated with the name. The reason I love the name is because the character in the book did something special. In the book he was trying to get a date with a retarded golem who was pretty. She challenged him to move all the buildings 3 inches to the west. Now this was stupidly impossible. He did all the buildings but one and that one didnt move because it was made out of impervium the most impervious stone to ever be impervious.