We have a huge open house party every year so we won't have a problem this year with it being ON Halloween. There is just too much going on in October to have an adult party and a separate kiddie one so we do it all in one shot. It's over fairly early (11ish) but I have to get up in the morning with my girls anyway so that's ok. I hire my babysitter and some of her friends to run the candy hunt in the cemetery and other kid-friendly games so the adults can relax! I've already booked a GREAT DJ for this year and sent out a save-the-date telling people to make us the very last stop on their trick-or-treat route.
Besides, I have plenty of Girls Nights Out with my girlfriends during the year so I don't mind sharing the party!