It’s pretty simple, I wear a lot of tie-dyed stuff, just sort of makes me stand out a bit, so I chose it for a name. I make tiedye too, shirts and socks and the like, so it works.
Plavacek is the hero of a Czech myth.
Basically, I HATE having to re-select a screen name, and so far, this one has always been open, so this is the one i use.
yawn
Mine is a great movie and a kick-ass song.
Hillbilly logic 
I am like SO unimaginitive. Carina is my RL name. I was named after a boat. I used to be 42. I think I too must e~mail Tuba Diva to get it changed to something else…perhaps I’ll just drop the “42.”
I’m a chief.
My name is Scott.
Hence…
The name our grandmother had for my sister and I. We were always her “Two Ones”.
Mine’s boring. IRL, I’m Caz. My SO has nicknamed me Cazzle. I don’t know why I didn’t put a capital “C” on it, I can only assume I was being lazy that day (or eating, and typing with one hand)
I used to use the online nick Maharet, after the character in the Anne Rice vampire books. She recorded all her mortal descendants for thousands of years, and had the coolest family tree, best if you read the books yourself, and I like to dabble in family history. However, I got sick of explaining to everyone where it came from, and I attracted a lot of freaks in some chat rooms (like the guy who told me he and his ex-GF used to drink each other’s blood). Cazzle is safe, and rarely taken, and I have a fall-back nick which is NEVER taken if I need it
A famous race mare with a spectacular, and tragic, story was my main inspiration. You can read about the real Ruffian here: thoroughbredchampions.com
That, and I also just love the name and idea of being a “ruffian!”
I am a dragon. I have co-starred in a trilogy of novels by Graham Edwards. I get vegetable jokes all the time, and last time I searched for my name to see if anyone had posted about me, it turned up a couple of cooking threads.
Lives by the sea. Widowed, from a guy that went to sea. Good friends with a guy at sea. See…
When Windows 95 first came out, my bussy the programmer edited the code to make File Manager into File Mangler. I thought it was funny. Then I tried USING Windows Explorer and eventually had him edit mine to read Xploder instead.
I worked my way through high school and college as a disc jockey. My initials were “T. V.” so my first program manager made my program “TV Time on the Radio” (In those days you couldn’t be a top 40 jock without a catchy on air persona). Later, when I got into newspapering, my editor gave me a column called “TV Time”.
I edit my own paper now but have kept the column name.
(possibly interesting to note: I’m not a big TV watcher)
I used to play a FPS game called Half-life. I wanted to pick Raven, It having ties to Death and wisdom, I picked it, Unfortunately it was taken (go figure) So instead of being Raven1 or 1Raven, I gave it a brief thought, and thought of a White Raven, White suggesting a purity like fresh fallen snow, (Pure Death) and my known online persona became WtRaven.
WAG: Elf-cleaver?
Gosh… well, when asked for a name, I typed in “Frannie,” cuz that’s my name. I didn’t know how complicated this stuff can get. 
**The Phantom Wombat **
“Who was that Masked Marsupial?”
Correct! First person ever to get that.
Song by Primus
“I remember it as if it were a meal ago.”
Said Tommy the Cat
as he reared back to clear whatever foreign matter may have nestled its way into his might throat.
Many a fat alley rat had met his demise staring point-blank down the cavernous barrel of this awesome prowling machine. Truly a wonder of nature, this urban predator. Tommy the Cat had many a story to tell, but it was a rare occasion, such as this, that he did.
I liked the song. Thought it was a cool name. Looking at all the other screen names being used, I knew that I couldn’t use something as ordinary as my name IRL.
Primus rocks.
Slortar was supposedly a Lord of Chaos in Michael Moorcock’s Stormbringer/Elric books. According to the game based off of it, his province was “evil wisdom.”
I always thought it was a really good name for a generic evil overlord type…
Tranquilis==Tranquility, as in Mare Tranquilis, the Sea of Tranquility, the sea from which I emerged a Shellback (Hail, Mighty Neptune!). My Chief had a strange sense of humor…
Besides, someone keeps registering ‘Maskman’ (I’ve a strange sense of humor, too!), and I don’t like changing handles.
Bonus points to the first to correctly cite the origin of ‘Maskman’.