Since Halloween is twice as nice as any other holiday, it gets two posts instead of just one.
If you're looking for a good trick-or-treating prank, try this one:
Begin by shopping bright and early tomorrow morning, November 1st, to get bargains on all leftover Halloween items. Specifically you are looking for small decorative baggies. Then begin collecting condiments each time you eat at a fast food restaurant. Barbecue sauce, Ranch dressing, mustard, ketchup, mayonnaise, soy sauce and salsa are just a few simple examples. You can also adapt this to be used for sit down restaurant visits as well, since you can just as easily take the Sweet N Low or Equal. A few days before Halloween 2012 comes around, take 3-5 packets of condiments and place them in the baggies. Tape them shut. When Trick-or-Treaters come around in search of sweet candies and chocolates, they instead will receive a small treat bag of liquid toppings. It does good to break up the monotony of treats kids receive.
And in case you're wondering, yes. I did do this. All of my friends who trick or treated at my house in 4th grade got a bag of condiments.