Give each of the players a bag with 10 pieces of wrapped candy in it. Have the players write their names on their bags so that the bags don't get mixed up. Decide on a time limit. If you are giving a party, you could keep the game going the entire time, even while you are doing other things. The object of the game is to catch people saying one of the following words:
HALLOWEEN, CANDY, WITCH, PARTY, GHOST, PUMPKIN
It might be helpful to write the words in large letters on a piece of paper and tape the paper up where everyone can see it. If you catch someone saying one of the words on the list, that person has to give you a piece of candy from their bag. The person who has the most candy at the end of the game wins a prize. And, of course, everyone gets to keep any candy they have left in their bag.