It seems appropriate.
Dressing up isn’t for the kids alone, even if the search for candy is. There’s all sorts of parties involved, costume balls and such. Whether you spend a lot of time fighting evil from beyond the Veil, or causing evil here and now, you may need some time to kick back, relax, and giggle quietly at the superstitions of the mundane masses. Let this be your guideline.
Amoromancy: Probably more likely to hang out in the bars than go out in pursuit of sweets or mayhem. Something seductive, probably; a vampire costume perhaps. Not Dracula, the more modern vampires.
Annihilomancy: Sternos are going to go more with the tricks than treats, ranging from egging cars to soaping windows, and the old favorite of a flaming bag of dog excrement. How about an orange prison uniform? That’s probably where they’ll be sending you if they catch you, especially since you probably have ties to arson in the surrounding area.
Bibliomancy: You could go as your favorite author, or alternatively, as Gutenberg. Dressing up as a giant book would be interesting, but movement might be awkward.
Cliomancy: Go as an ancient Atlantean, complete with crystal scepter and Pyramid sigils everywhere.
Cryptomancy: East Cryptomancers could go as P.T. Barnum, or any famous con artist. Western Cryptomancers would be more suited to Sherlock Holmes. Learn to play the violin for added friend-impressing-power.
Dipsomancy: …let’s face it, you’re not going to wake up until November third anyway, so it doesn’t ultimately matter.
Entropomancy: James Bond, Racecar drivers… hell, Indiana Jones is a big risk taker too. Write up all your favorites and number them, then roll a couple dice. Or even better, find an online catalog and mash in a random string of numbers and letters for the product code, and take the first one that’s valid. (Warning: You may end up with a costume that does not match your sex, such as a guy going as Glinda the Good Witch from the Wizard of Oz.)
Epideromancy: Re-arrange your face and go as a Picasso Painting. Seriously. As long as you remain largely inexpressive, people will think it’s a really good mask.
Geomancy: Go as a Construction Worker, or better yet, a postman! Complete with full-auto firearms! (Note: Don’t use real firearms unless you really think someone is going to attack you. Just to be safe.)
Herpemancy: Snake Charmer, dude. Remember that if you take one of your friends along, some people WILL freak out. Keep him or her near you at all times and make sure the species is non-poisonous.
Iconomancy: …this should be obvious. If you really can’t decide between all your different idols, then you might consider going as a Papparazi.
Infomancy: Going as a computer moniter, tower, flashdrive or video card may sound creative, but you will be forever branded as an uber-geek as a result, if you’re not already named as such. You might consider going as a public official you wish to lampoon, like the President, the Mayor, or a Celebrity. It depends on your inclination and free time.
Irascimancy: If you’re not hanging out with the Sternos, screwing up people’s houses and cars, you’ll probably be trying to piss people off with an offensive costume. Going to a party of primarily black people as a Ku Klux Klansman, or perhaps a group of pro-Bush white people as an Arab Muslim, might be enough to charge you up. The problem is going far enough past “good taste” to get people angry, but not so far as they drown you in the punch bowl and bury your corpse in the basement. Use discretion.
Kleptomancy: Let’s see here. Dark night, when the cops are busy chasing kids who T.P.ed the city park, and people are all the more willing to beleive anything they heard in the dark was just their imagination. Yeah, you’re probably going to be working tonight. If you’re set for charges, though, or laid up, you could always go as a famous theif. For women, the obvious choice is Carmen SanDiego. Men, on the other hand, have more options, ranging from the bandits of the old west, to the Phantom from the Pink Panther movie, to Garrett from the Thief computer game series.
Mechanomancy: Assuming you actually remember the Halloween is coming up, you could go as many different things that a normal human wouldn’t be convincing as. A centuar, perhaps, if you could construct the appropriate hind legs and trunk. Or maybe a spider, with extra mechanical arms. The possibilities are limited only by time, parts, and your own imagination.
Narco-Alchemy: Flip a coin. If it’s heads, go as a hippie. If tails, go as a bong. If it lands on its edge, you’re on your own.
Oneiromancy: Well, the dark circles under your eyes will make you a very convincing zombie. You’ll also be shuffling a lot. Sounds like a good match, doesn’t it?
Personamancy: Anything with a mask will do, and there’s a lot of masks available at Halloween. Unless they get back ordered. If you want to make a big impression, “Visage of Terror” is an excellent choice. Unless they all spaz out and kill you.
Plutophagy: “Halloween is nothing but a manipulation of the old pagan holidays to shove cash into the greedy clutches of the candy industry blah blah blah…”
Plutomancy: Pick your favorite president. Shouldn’t be too hard.
Pornomancy: Any sort of femme fatale would fit the bill, at least for female pornomancers. Male ones may have to settle for dressing up like the Goddess’s co-stars. And dressing up is meant literally in this case; the police are already looking for trouble, they will very quickly notice indecent exposure.
Thanatomancy: Scythe. Black cloak. Bones. Do you need a picture drawn? It may be cliche, but it’ll draw less attention than going as your favorite serial killer.
Urbanomancy: Going as a Homeless guy is fitting. Plus the costume is easy to throw together.
Videomancy: Going as your favorite character on your fetish show SOUNDS like a good idea, in theory. Be aware, though, of differences in height, weight, and especially gender. Do not cross these unless you have a friendly Fleshworker or Thespian to help out. For the sake of the eyes of other people.
Unique Schools: Sorry, you’re on your own.
The evil part of me can’t help but say it’d be more fun for an Urbanomancer to go as an ACTUAL homless person.
One of my guests at my house party (himself a UA player) went as a Dipsomancer; Lord Byron.
Given I was dressed as a biohazmat tech with a bomb manual under my arm, my own Sterno costume was.. well, blown out of the water.