My wife found this in our front yard. It seems to be part of a sprinkler system that some previous owner installed. When I flip the cover back and put my finger down in the hole, I would hit some sort of spring loaded thing and some water would come out. Although not anymore. I'm guessing there was some pressure in the line that bled off when I was playing with it. Anyway, it looks like you could put a sprinkler head on this thing. But I've never really seen anything like it. Unfortunately there's no obvious control panel or even a knob anywhere to turn the thing on. And I've not found anymore of these things anywhere else. Anyone have an idea?