Our Halloween parties started when the kids were little but it has now evolved into a mostly adult party, although kids are encouraged and welcomed to come and I always have kiddy food, drinks, and treats.
When my kids were little I would give out prizes for top voted costumes but we haven't had a costume contest in years.
My daughter Alexis asked me to revive the tradition. So this year we had a costume contest, complete with voting jars for each category, and slips of paper and ink pens for everyone to pick their favorites.
We also decided that if you win an award in one category, you could not win in another. That rule just allows more people to take home an award, but feel free to make up your own rules.