Is your dad George Costanza?
My username? Half of it refers to the character in “Death of a Salesman” and the other half is just made up.
Happy
I just dig that cat from the comic strip Mutts.
Lodrain:
Now, please, don’t do anything so irrational.
As for my user name…well, that’s pretty simple, isn’t it?
Chaim Mattis Keller
My name is nonsensical.
I picked it at the last second cuz the name I really wanted was not available. 
Not that I’ve ever seen a post by the person who has the name I really wanted.
Mine isn’t too hard to figure out for any classic rock fans…Zep refers to Zeppelin, as in Led Zeppelin, which is my favorite rock band of all time. The second part just refers to my gender. I nearly always refer to girls as chicks, something I found very chauvenistic a couple of years ago, and now find I use it myself more than most guys do! 
Belrix was Arthur’s Pendragon’s name while he lived with the Prydn in the book Firelord by Parke Godwin. In their language it means “Firelord”, a name I use in other places.
This is my all-time favorite book. Here’s a Review by regular person (with links to other reviews) and here’s the Book, unfortunately out of print.
Nott is a family nickname. One night I started telling a joke that ended with a highschool kid telling me, “My history teacher said I should ask you what my country can do for me.” About that time, I needed an internet name, and pow, there it was.
Pick up a copy of Being There by Jerzy Kocinski, or rent the Peter Sellers movie by the same name. Some years ago I used to post as K. Chauncey Gardener on web sites, but I abbreviated to Chance after a while. Since Chance was taken (though I’ve never seen anyone actually use this name on this board,) I tacked on the rest of it, fully acknowledging my namesake.
I know I’ve done this in one of the other threads, but here goes…
It’s my name.
Zev Steinhardt
It’s one of my favorite novels, by Isabel Allende. (I was a Spanish major in college.) Read it in the original, if at all possible. Part of it also resembles my name IRL.
And here I’d been wanting to start a thread along these lines, because I thought it was so original…oh well!
A word I created in high school.
Icono-, meaning something that’s idolized.
-plast, a unit of protoplasm.
Hence, iconoplast, an idolized unit of protoplasm. You may feel free to interpret this as you wish.
On the (admittedly rare) occasions where I post something witty, if no one acknowledges it I am disappointed.
To prevent this from happening to others, I will sometimes hijack a thread briefly just to send kudos to the poster. To that purpose, I want to publically recognize cmkeller’s comment above. It is so subtle that I’m not sure if everyone caught the joke. I loved it.
Mine’s relatively simple. My name’s Ron. I’ve loved the muppets since childhood, and had a way-cool Gonzo Tshirt that has since been ruined by an unforntunate bleach accident. People at school started calling me Gonzo in jest. For lack of anything better I picked it up as my AIM name. Since then, it has stuck.
My former name Frank the Lost Ramone was explained in one of them there other threads. My new name comes from a story arc in Spider-Man back in the early 90’s, Maximum Carnage. I use it for all my gaming needs, especially when I’m out playing laser tag…“You were hit by…Max Carnage!”
hee hee!
I named myself after Cold Stone Creamery, which is a chain of ice cream parlors that take a scoop of ice cream and smash candy or fruit or nuts or whatever you want into it. When my husband and I were first dating, we’d drive to the coast together and always stop there on the way - and I started calling them “Smashed Ice Cream Trips”, meaning we’d stop there on the way to wherever.
I have no idea what prompted me to use that as a username, though. I musta been hungry.
Was it lolagranola?
I’ve done this before, too. However, I will play along again. (seems I always do in these sorts of threads)
F_X
Mine was originally (a very very long time ago - Back when I first got internet access on AOL) a character from a rather awful book which I for some reason liked at the time. I think it was called “The darkness before the dawn” or something to that effect. Darksun book.
Since then I’ve just used it because everyone knows it’s me, regardless of what service I’m on. Although I suppose there are more using it now since the people at nintendo stole my name for some game of their’s.
Ahem. What I meant to say was that the reason I originaly chose it was that it was the name of a character from a book. Of course, it still is, that’s just not my reason for keeping it.
My reasoning’s two-fold…
I was re-reading The Hobbit and The Mangler at about the time I registered for my first board. Belladonna, the plant, plays a fairly important role in the latter story, so when I saw it in the former as Bilbo’s mother’s name I was struck by the coincidence. A user name was needed, my first choice (pandora, for those who care) was taken, and so belladonna it became.