Dressed as a Sloth
The Sloth Sin Station can be the first award of the evening and will set the precedent for the festivities.
The sinner won't know he's the winner when he walks in the door; he'll probably just think he was "too cool" to dress up for your party. The joke is on him! The person(s) who comes without a costume is the Sloth.
As a punishment for the Sloth's laziness, he/she must refill the drinks of all the party-goers who followed the rules and dressed in costume. Seems like the winner of this sin station is actually the loser. It's all in good fun!
Test of Greed
Some say money is the root of all evil; find out which one of your guests is willing to "sell his soul" for a few bucks.
This activity requires one thing: a five dollar bill.
Place a crumbled five dollar bill in a highly trafficked area at your Halloween party but make it inconspicuous (ie- under the kitchen table). The first guest to pocket the money is the winner of this game.
If a guest finds the money and attempts to return it, let them in on the "game." The more people that can be on the look out for the winner, the better. The prize? Well five dollars, of course!
Pride: Have a Brag-Off
In this game, have a brag-off. The object of the game is to see who has the most pride!
Have a costume brag-off - whoever convinces the most guests that his/her costume is the best, wins!
The parent who carries the most photos of his child in his wallet is the winner. Bonus if he carries around kid's report card or crayon drawing!