10: Completely forget to button your fly/close your robe. This will scare the children. Fair warning: Depending on how many stay-at-home moms are in your neighborhood, this may attract unwanted cougars.
9: Be the dick on the block that hands out pennies. I always hated that dick. Never went to that house.
7: Answer the door blackout drunk with a bottle of whiskey sticking out of your pocket.
6: One by one turn to each trick-or-treater and say, and who are you supposed to be...OJ Simpson?
5: When they ring your doorbell, open the door in 1820's English garb and start singing Oh Holy Night...that'll throw the little rejects for a loop. It'll also get them asking their parents about Christmas very early. The parents will never let them come back.
4: Put a sign up on the front door that says please go to the back door. On the back door put up a sign that says please go to the front door. Tape the reaction...put it on youtube.
3: Put aluminum siding over your front door.
2: It's simple really. Purposefully buy pre-packaged candy, and then take it out of the package and give it to the kids. Loudly explain to the parents you don't f*&#ing care what your local newscaster says...candy is better out of the package.
1: And the number 1 thing you can do to make sure trick-or-treaters don't return to your house ever again: Three words: Fruit Stripe Gum.