For the last couple of years, I've had this long black cape with a multicolored silk lining. So I can be a magician or snake handler or whatever I want.
I stopped trick-or-treating long ago; now that I'm an adult, I'm more likely to help hand out treats or help direct a haunted house or something. That's always fun.
One year, when I was 14, I helped out with a "death room" at a party. The story with it was that two teens had sat up waiting for their prom dates to call, and they were kept waiting so long at the phone that they died of boredom.
In the "death room," there were two dummies in black clothes and Scream masks slumped over in chairs...or so it seemed. One of the dummies was actually a live human being (me). We'd have unsuspecting kids come in, pick up the phone when it rang...and then I'd let them have it with a can of silly string. Good times!