Have posted about this a few times elsewhere in the past (in the Discord, and on /r/tipofmyjoystick, to name a couple) but nothing ever came to fruition. All I had back then though was a description, so I decided to do a couple of mockups today in the hopes that someone might recognise it and be able to help.
So, to start, it was an educational game for DOS. You played as a black ball with arms and legs, navigating your way around an isometric hub world to access different minigames (and, if I recall correctly, there was some sort of pyramid in the center, as pictured below):
I recall there being a few minigames, maybe 4 or 5, each represented by these platforms. According to my vague memory, this included a maths game and a spelling game, but the only minigame that I have a distinct memory of playing is the hat stacking one. In this one, you would have to stack different hats on your head as they fell from chutes above, matching the one on the screen in the middle (pictured below):
Though I should mention, I'm far from 100% on the hat stacking game; the screen in the middle may not have even existed and the goal may have simply been to just get all the falling hats...
Anyway, now that I have these mockup images, I might try the other places I mentioned again too, but figured I'd put it here first and see what happens.