We have a great tradition of adult Halloween parties here in the US, right up there with New Years eve for drunken wild times. Women like to dress in slutty costumes, slutty vampire, slutty nurse, slutty gypsy etc.. Men can dress as a pirate! or wear a gorilla suit, for some reason women like getting groped by someone in a gorilla suit, some sort of primal urge? You can wear a mask and behave inappropriately and people don't know who you are.
All great fun perhaps you are missing out on?
^^^^^^ sounds like fun! I'll be into it! We had similar fun in Europe during the Carnaval time just before lent, Mardi gras in the US and OZ but it is not only for gay peeps, good excuse to wear a mask and go around, drink a lot and behave badly undercover! 
