Okay, here's one that I remember a colleague and I adding to a FactoryLink App back in the early 90s:
There was a screen for pump control at a settling pond, and if you clicked a certain, small object on the screen then it opened another screen with an underwater scene that had a crab scurrying along the bottom, fish swimming in the center and ducks swimming across the surface. The object of our little "game" was to click a duck and release a "poop ball" that, if timed correctly, would miss the fish and hit the crab, causing the crab to shrink until it disappeared. We put far too much time into that, but we were on-site and waiting for some contractors to finish some work before we could resume testing our software.