Used to make it so that you press the button once and it disables the enabled event and enables the next one in the list. It can save you a hell of a lot of SetEventEnabled/ToggleEventEnabled.
A fun game:
Put a whole heap of player effects OnActivate on a block, disable all except one and put all their numbers into a ShiftEvenEnabled list. Every time you press it, it cycles to a new effect, then get a whole bunch of people to take turns pressing it. Last person alive wins :3