Indiana Jones Epic Stunt Spectacular Interactive Show Control
Back in my 1990 Yale thesis, I wrote about the technical details of the show control system for the Indiana Jones Epic Stunt Spectacular at what is now called Disney Hollywood Studios. In those days, you had to work really hard to pry any information out of anyone; today, on the anniversary of the 1989 opening of the show, the Disney Parks Blog has a video where you can see, at the :56 mark, the actor controlling the spikes in the "spike minefield" scene:
Watch carefully where he puts his feet--the system has also likely been "enabled" by a technician in the booth. For more on enabling concepts, I know a book that explains it...
This is a really fun show and worth a look if you're in Orlando!