Vampires, zombies, ghosts, and ghouls. A haunting - perhaps The Turn of the Screw
Halloween is a bit of a silly season, yet the bright orange pumpkins and scary masks are harmless fun. When else do you take candy from strangers? Play ghostly organ music, conjure up a phantom, or watch old Vincent Price or Bela Lugosi movies. I can remember, as a kid, tromping about our neighborhood in PA on a Halloween night with my costume on and a winter coat (due to snow flurries). That diminishes the oomph of the presentation.
I vant to suck your blood - say it with your best Transylvanian accent. Or dance the Time Warp again a la Rocky Horror
Eat gobs of candy corn. Just don't step on the scale. EEEEEEK!!!