I remember one tourist in GTNP asking if they "turn the Tetons off at night." None of us could quite figure out what that meant.
A buddy who worked in Yellowstone told a story about a couple park employees who had a wheel on a metal pole, and before Old Faithful erupted they ran out in front of a group of tourists and started cranking the wheel like they were turning it on. When the eruption was done, they turned the wheel the other way like they were turning it off, and then they got the hell out of there.