Wow, that's so sad.
At our school, we have a whole festival! The Halloween Festival takes place at night.
During the week before the Festival, all of the children carve pumpkins in class. Then the pumpkins are put out in the meadow and lit that night as a path to follow from one "station" to the next. The "stations" are where the children get their treats.
Each class chooses a theme for their station, then creates a setting for that theme. Last year my daughter's class did a ghost pirate ship, which we made out of heavy cardboard and wood, and painted black, then used glow in the dark paint to outline it. Her teacher dressed as a pirate, and handed out the treats. It was awesome. For my son's class - since they were studying Ancient Greece - we made a mini-Parthenon and dressed his teacher as Athena (to hand out the treats). This year, since my daughter's class is learning about farming, we chose Johnny Appleseed for the theme. Her teacher is going to dress up like Johnny - complete with pot on head! - and hand out apples for the treats.
Anyway, each class makes their station - always very creative and cool - and the teachers hand out the treats - which have to be nut free and preferably as little sugar as possible - and all the families do the Pumpkin Lantern Walk together to see the stations and get the treats.
Afterward, we have a big bonfire and cider and baked goods. And the children run around like banshees! : ) Very, very fun and looked forward to by the parents as much as the children.
As for costumes, the limitations are: nothing gruesome; they can be scary, but not too scary (because our school is Pre-K through 8th); and NO media figures. (Because our school is anti-TV/video games/computers until the children are in high school.)
I love our school -- it is so awesome!