How do I make my adult halloween party really fun?

I'm hosting an adult halloween Party this year, and I was going to try to come up with some games to play, but a few people I have spoken to have said, that most adults don't like to play organized games and just want to chat. That being said, I have been to some pretty boring Halloween parties over the years, and I want my party to be remembered as being a lot of fun. I plan on makeing lots of cool, scary and not so scary food, providing some alcoholic and non alcoholic drinks. I was thinking of doing the typical costume contest and possibly have people brink Jack o Lanterns and do a contest for those as well. Can you think of any other ideas that would make this party fun? We also plan on having a firepit in the backyard with hay bales for people to sit on and having the game Rock band in the basement for people to play.