Back in 1986 I was asked to build a set of "game show" buzzers that would allow a number of contestants to hit their button and it would show who pressed first. I ended up creating a system that used relays that would latch the first button pusher's indicator ON and cut power to the other controllers at the same time. I came up with an improved design to allow an arbitrary number of buzzers to be daisy-chained but they didn't want to pay for version 2.0. It was a fun side-hustle for this high school Radio Shack employee.