Richard Garriott, aka "Lord British", creator of the "Ultima" game series, used to do something fun for Halloween - a real life haunted house fantasy adventure.
Tickets were given for free, first come, first served, and some lined up well in advance, creating a makeshift hobo camp outside his property. It took 400 people to create it each time it was held and 200 people to staff it. He spent $100,000 on the effects. Here, the Medusa on the second floor:
Photo: Richard Garriott