1) Distribute costume-appropriate candy. Give raw meat to carnivorous animals. Batteries to Transformers. Razor-embedded apples to goths.
2) Ask the kids what their favorite candy is and write it down. Then close the door and time how long they wait before leaving.
3) Strenuously argue with children over what their costumes are. "No, you're not a Jedi. You're definitely the Karate Kid."
4) Claim you are all out of candy while you are munching on Tootsie Rolls and holding a large bag of them.
5) Ever notice how much individually-wrapped laxatives look like candy (hint hint)?