I had a friend who taped cigarette butts, banana peels, eggshells and other assorted junk to his clothing and went as “a mess”.
The GQ forum is for question with factual answers. Since you’re looking for suggestions rather than facts, I’ll move this thread to IMHO.
bibliophage
moderator GQ
Or, glue on a tissue box and a small battery-operated light, maybe a pile of paperbacks. Tell people you’re One Night Stand.
Then you can break it and be a Crack-pot!
::Zing!:: 
A goth! Har har!
It’s a bit elaborate, but you and your SO could go as a hot dog and a bun. 
Tape a picture of Sigmund Freud to a slip.
Where do you work? Are you going to any work parties? I used to work in the auto parts industry when I was a 20 something. I got a big box, and painted it like a Delco Oil Filter, then I wore blue tights and a leotard under it…
If your job isn’t just in an office and is a bit specialized maybe you can do something like that.
My mom used to work at a city utility, lots of people would dress like different aspects of the utility (a lightening bolt for electricity, a shut off notice, etc).
A couple of friends of mine once went as a huge spider (the girl) and a can of Raid (the husband).
Another set of friends went as pregnant nuns (hope I don’t offend any catholics, I’m non-denom).
Another guy went as a plate of spaghetti, he got a big flat cardboard “plate” and made a hole for his neck in it. He got several mop heads and cut the strands off and arranged them along with some goop he made up to look like spaghetti sauce, then, he painted his head to resemble a meatball.
When I was pregnant with my daughter one year, I went as the Great Pumpkin (duhh, THAT one is a no brainer hehe).
My mom and dad went as Raggedy Ann and Andy one year (they were really cute!!!).
Have you tried just plugging “halloween costume ideas” into webferret or something?
(webferret=better than google).
Paint yourself orange, die your hair green and go as a big carrot. Clothing is optional of course.
I’m going to be a carrot. I got a big sheets of orange and green paper from the school supply store. I plan to staple my costume together just before we leave to go T or T’ing.
(I actually spent alot of time on the kids costumes (Captain Hook and a witch).
Put a condom up each nostril and when people ask what you’re dressed as say, “Fuck knows.”
A couple years ago my step dad’s girlfriend made him a Bud Lite can as a costume and somehow someway got him to actually wear it(he was NOT the kind of guy who liked to dress up funny)
There exists ONE picture of him in this get up and he looked sooooo embarrassed…of course the thought never crossed my mind to tease him