Seriously, the people saying Halloween III: Season of the Witch are exactly right that this film fits in HDTGM perfectly. Here's why.
1) Like others have said, it's completely removed from the rest of the series. That's something crazy to latch onto right from the start.
2) It has the amazingly campy Tom Atkins and Dan O'Herlihy as an eerie Celtic man.
3) It just had a blu-ray rerelease, and it's part of a storied, famous franchise. So people are aware of it even if they haven't seen it. They'll be intrigued for sure.
4) Take a look at this premise: seemingly inhuman people have killed a man and have links to a halloween mask company. Upon further investigation, a huge conspiracy is revealed. Needless to say, the conspiracy is ludicrous and amazing.
5) Here are some things that are involved: magic lasers, overly agressive eye-poking, pranksters who don't really ever pull pranks, and an animatronic grandma.
There are more plot jumps and devices that I don't really want to get into because they're better left unspoiled, but trust that they're exactly the brand of insanity I always look for in HDTGM.
And I think this film works better than ones like Hausu or Thankskilling. (that second one isn't even a Halloween film but still) Hausu and Thankskilling and other titles that have been mentioned are intentionally psycho. The craziness in Halloween III isn't as self-aware, making it all the more fun.
This movie is one of my favorites because it's so out of its mind, which is a feeling I hear you guys having a lot with your more eccentric movie selections. I guarantee you'll feel that way about Halloween III, and if you don't I pledge to donate a kidney to any of you should you ever need one