Are all Halloween party conversations limited to total frivolity/idiocy? Am I just going to the outstanding fabulous Halloween parties, in terms of intelligent conversation?

And there really isn't an analog in physics to dress as. It's not like Harry Potter conventions feature people dressed as Green Lantern, mostly -- at least, that's not the part he's sneering at. If someone was interested in textiles in a particular historical period, I wouldn't find it at all surprising if they had period dress at their disposal. Many of the historians and history buffs I know have at least looked into what that would involve -- that is, many of the female historians and history buffs. Rather fewer of the males.