MPSIMS, “mip-sims”, just doesn’t flow for for me. Therefore, I have always referred to this forum as “Ms. Pisms”, which leads to much confusion when I try to figure out what the heck MSPSMS stands for.
I think of it as “M-P Sims”; think of a military police officer, if personification is your thing.
I just call it Em Pee Ess Eye Em Ess. 
I’m another Em Pee Ess Eye Em Ess-er.
You want to hear something kinda funny? holds right hand up I work with a woman whos initials are, and this is the gods honest truth, M.P. Sims. 
…which is exactly how I think of it. MP Sims.
Impy-sims. It’s the same pronunciation Scotti and occ favor, but I think it catches flavor of the forum better. 
I’m a mip-simser, myself. Which is indeed mundane and pointless.
I just say “mundane pointless sh*t”
Me too: MP Sims. (Member of Parliament, name of Simms - probably a Conservative).
Hmmm, MP Sims could work. I’ll try it out for a bit.
No, no, no, no, no.
“My Pahzzims”
I call it “more pointless sh*t …”
I call it: 'Pizzims.
I call it mmm-p’sims. The “mmm-p’” is very vaguely like “oompa” but not really.
I call it “mip-sims.”
I also pronounce IMHO as “I’m hoe.” Am I alone in that? 
I’m with the “Em-Pee Sims” crowd.
And IMHO is “Ihm (short i)-Hoe”
Another “Em-Pee-Sims” fan, here.
Okay, surely I’m not the only one who pronounces it Ms. Pisms??
And I also call it “Ihm-hoe” - sounds egyptian.
I call it “Mindless Pointless Stuff”. Yes, I know it’s Mundane and not Mindless, but I thought it was Mindless at first and the name just stuck from then on.
On a related note, my husband–who doesn’t read the boards too often–refers to the Pit as “the Fart Forum” after reading the infamous Fart thread a few months ago.