I’m obsessed with felines. 
I named myself after my cat. Which I think is a very SDMB thing to do. She was (RIP 
) a black beast. When I needed to come up with a name I looked around and there she was. And I’m something of a black beast myself. So it seemed to fit.
It’s like being a pet peeve only bigger and nastier.
Rather unimaginative in my case; my previous one was essentially my real name. I decided quite a while ago that I wanted a little more anonymity, so for a new name I just picked an intentional mispronunciation of “Canadian” (which I am 
)
norinew, I know you are really Norine W. because of other threads about Doper names, and I STILL think of you as nori-new.
“freckafree” is what my sisters and I decided our defective Casper the Friendly Ghost talking doll was saying instead of “friendly ghost.” I use it for lots of things. My iPod is named “Freckafree’s iPod,” because it amuses me to see that scroll past on my car stereo. (Yes, I am easily amused.)
Le Ministre de l’au-delà means ‘The Minister from Beyond’. It comes from the song "2033 " by La Bottine Souriante . I just liked the surreal notion of a Government ministry from ‘beyond’.
The unfortunate side effect is that it gives people the impression that I’m a Francophone - Francophile, certainly, but I struggle with my second language like many other bilingual Anglos…
My original username was hrhomer, which is generally what I use on messageboards. It’s from the Simpsons - "Home Run Homer. But I was away from the SDMB for a long time, and I have no idea what email address I had connected to that name, and don’t remember the password.
I am a user of the website Where’s George?, which is where I got my current name. Not sure where I got the 04 part…
Joe
Antinor is a character name I invented and started using in a MUD many years ago. I started using an email address and AIM as Antinor01 a long time ago as well. These days most account I start have Antinor01 as the name. It’s easy for me to remember now, so that’s why I go under nearly everywhere.
I used to sign all my posts with my real name (Russell) but got out of the habit.
Neil Gaiman and Terry Pratchett’s Good Omens, it’s as simple as that. As much as I love Pratchett’s Discworld series, that book is even better IMHO. And I fully sympathise with Aziraphale’s attitude to books.
Oh, and a bit of trivia for you, Merkwurdigliebe (Merkwürdigliebe?): The German title of Dr Strangelove is simply “Doktor Seltsam” – which retranslates to “Doctor Strange”. I suppose that once you’re in the language he’s meant to be speaking, the joke just doesn’t work – don’t remember what the German version makes of the dialogue that mentions the name change though.
My username everywhere else is silvercat, unconsciously taken from half of my two favorite cartoons (Silverhawks & Thundercats). My online persona as Silvercat is a white and blue anthro tiger with wings, thus Silver Tyger Girl. The ‘y’ is because I’m special.
Not really. It’s also from Thundercats.
Shagnasty is what my best friend called me in high school. Many people assume that it is dirty when it is not but I can understand why they think that. It actually goes back at least 100 years and probably more and it appears to be British in origin.
Mine is from a defunct Russian humor magazine.
I take my name from this fictional, Falstaffian Polish nobleman. Perhaps someday I’ll get around to asking the admins to change the “l” to “ł”
My best friend and I used to say ‘‘olives’’ to each other in lieu of ‘‘I love you’’ (Olive you.) It became a whole big thing, to the point that my mother-in-law even says ‘‘Olives’’ instead of ‘‘I love you,’’ and I continually get olives-related gifts from my friends and family. My birthday is March 4th. My best friend came up with it way back in the day when she was trying to set me up with an AOL account. We loved the visual imagery of olives marching (we were also in marching band together, and that’s how we became best friends.) For a while I felt like I had outgrown it (this whole thing started in high school over a decade ago), but I think I’m reclaiming it. I can try to pretend I’m not silly, but eventually people are going to figure it out. At least this way they get a hint right off the bat.
Fun fact: I think olives are one of the most disgusting foods in all of existence.
I stole mine.
“Otto da Fe” was a name my brother used frequently when he needed a throwaway answer for a multiple-choice test. It just seemed to fit, somehow.
Obvious point of origin is the Inquisition, though knowing my brother’s taste in humor (which I happen to share), it’s probably also tied to Tom Slick’s nemesis.
Camping nickname.
One of the things I used to do on occasion to reduce stress (ha!) was to role-play on on-line communities like NWN. After a while “Hail & well met” was getting really stale/tired/old, so I’d come up with entire characters built to play on puns to break the ice. One of these was “Count Blucher” who would approach a group of characters/gamers and ask,
“Pardon me, but have you seen my wife”?
“And who would that be?”
“Frau Blucher…?”
Horse Whinny
Mel Brooks / D&D : Who knew? 
India. 1979. I was on the fourth night of a two-day opium and sex orgy with a high-ranking Madagascaran general and a half-dozen east-Asian college co-eds/call girls.
The general and a girl named Nomi went out for cigarettes. I was eating the last of a lemon cake, and trying to make conversation with one of the hookers, but her English was far from understandable in my opium-induced state.
I told her “That’s enough honey. No more talking.”
She said, “Lendon vake?”
I said, “Honey, let me eat my lemon cake cuz I want to go to bed.”
“Lendon ved?” she said.
But at that point, my last hit off the pipe did something to me, and her words began to echo off the walls.
"Lendonvedenlendonvederlendervedendervedderlendenvedderlenderveddenderlendervedder…
“Len…der…ved…der.”
I was lost in the sound of her voice bouncing around my eardrums, and I hadn’t noticed the general had come back, and was standing over me. He was repeatedly asking me if I was okay. I finally realized he was talking to me, and I said “Yeah…yeah.”
Then he asked, “But are you happy?”
I looked at him, nodded my head slowly, and said, “No.”
My first name is Rick.
My last name is Jones.
So, I’m not exactly Mr. Originality.
First, it’s a transfer. The name I use here is a name I used several years ago on a message board dedicated to Hawaiian politics.
Second, I came up with the name based on my readings of some political boards elsewhere, where members had a tendency to base the names they used on political figures of the past. William F. Quinn was Hawaii’s first governor after becoming a state, and struck me as a suitable figure to filch the name of.
As for why I still use it: I’ve never felt a need to change, it gives no secrets away, and it (in my mind, at least) manages to be of some note and also somewhat anonymous at the same time.
Mine comes from a certain well-known spaceship pilot. I spell it with two Fs because that generally means it won’t be taken…