Hell, that just changed in a hurry. M.P.SIMS!
Damn you, Coldy Clogs. 
“I thought: opera, how hard can it be? Songs. Pretty girls dancing. Nice scenery. Lots of people handing over cash. Got to be better than the cut-throat world of yoghurt, I thought.” - Seldom Bucket
Empy-isms
It was only last month that I realized that I had mentally reversed the ‘i’ and the ‘s.’ Thus, my pronounciation is somewhat dyslexic. Can’t break the habit now!
I pronounce it “em PIZZ ums” (almost like FrankD6). But before I was enlightened, I pronounced it “M-P-S-isms”.
A Slightly Altered Perception of Reality…
Chrome Toaster
M.P. Sims. Usually.
When I’m not logged in, but Lex is, I’ll ask “What’s new on M.P. Sims?” or “What’s up with Mundane Pointless today?”
~handcrafted signatures since 1975~
M.P. Sims – it never occurred to me to call it anything else, oddly.
Catrandom
I’m similar. I actually say it: Empysisms. I know that’s not how it’s spelled, but whatever. 
Em Pee Ess Aye Em Ess
(I do a lot of work with IBM stuff.)
You already know this, but I’ll throw my vote in anyway. I say M. P. Sims
Work is fine for killin’ time, but it’s a shaky way to make a living.
I used to call it Em Pee Sims, along with a lot of people apparently. But now I think I’m going to have to start calling it Em-possums as per your suggestion…
I spell it out letter by letter, as if it were NFL or FBI.
I pronounce each letter individually, like tomndbebb and MoosieGirl. Either that, or I’ll say “Mundane Pointless Stuff I Must Share”. I remember at the So. Cal Doper’s meeting Melin was looking at me funny when I said Emm Pee Ess I Emm Ess.
I’m a mip-simmer.
I’m a mip-simmer.
Watchin’ posts go by -
Oh, my, my.
tomndebb, for some reason, your post made me think of an old gag of my mother’s.
F U N E X?
S, V F X.
F U N E M?
S, V F M.
Y, L F D M N X.
Why, oh why, do these things stick in my brain?
I dunno why, but I think of it as:
PMSisms
But that would probably apply more to the Pit.
Dyslexia can be fnu.
I spell it, like Tom.
~Kyla
“Don’t Do It.”
I pronounce it as if it were a MpDonald’s product.
i say
m-p-sims
yeah…
Ohmygosh - it just occured to me - Mickey Pees!
em-piz-ems
A woman needs four animals in her life: A mink in the closet, a Jaguar in the garage, a tiger in the bedroom, and an ass to pay for it all.
—Zsa Zsa Gabor
The general consensus of both the NYC and the Spiffled/Chicago SDMB crews is “mipsims”.
em-puh-SIMS
Ass-Toaster Extraordinaire, SDMBSRC