Weeelll...

fast_max's Halloween party:

childhood_vader dressed as Gillian Anderson.
delamarck dressed as Ichabod Crane, the schoolmaster from Sleepy Hollow.
drgatesjones dressed as Sybil - except that Sybil didn't show but the other 38 personalities did.
dumornes_girl dressed as Jim Carrey, though it looked more like Nosferatu the Supreme Vampire.
junior_desade dressed as a character from Harry Potter and the Successive Bone.
simonarchangel dressed as a monster from a Resident Evil game.
warden_betrayer dressed as Lady Godiva without the horse and far too little hair!.
wild_maggie dressed as Guy Fawkes but the exploding barrel of dynamite didn't go down too well.
wizard_dark dressed as the Fuzzy Power Ranger.
wizard_light dressed as Kurt Cobain.
wizard_nobility dressed as Alyssa Milano.

Throw your own party at the Hallomeme!
Created by sigma7: More info here.

Oh, and I typed I'd be dressed up as Batman...