I have been having a hoot going through this site! Not quite like being there, but still a great vicarious experience.
Makes me think of Halloween at Boomeria, a complex of tunnels, laboratories, castles, dungeons, etc. up in the Santa Cruz mountains. The big difference with Boomeria is it's permanent. The owner used to periodically open it up to friends of the teenagers (then thirtysomethings) who helped him build it. I can probably still find my way through the catacombs in total darkness...