We have an awesome tadition. My friend is into movie editing and special effects...so he decorates his house (a big old colonial that, from the outside, could easily be some kind of haunted mansion with it's front deck all covered in ivy and whatnot). He makes the most insane movie-style effects for his decorations.
What we do is, we buy a ****load of stuff we like. But then we blend into the scenery in costume with his special effects ****. Our goal for the night: scare away as many trick or treaters as we can. At the stroke of midnight, the remaining candy and food is ours....
This is also simultaneously a party, so we have many spectators hidden in the windows while the main bunch of us do this. Great fun.
My fav thing about Halloween is that it's a night when normally conservative and cute girls will dress like skanks like they always wanted to, just because it's "a costume" and won't ruin their rep. The perks of being a small town guy...heheh.
EDIT: Best Costume...wore a Curt Schilling Jersey and tied a huge bloody towel around my ankle. Hehe.