Little me (7-9 range? Before 10 and the Pokémon Times) once upon a time made a game.
To play this game you needed a piece of paper and a pencil and that was about it. I'd draw a map on the paper with some obstacles (giant snakes that blocked the path were popular, as were lava pits and wolves marked with 'X's. I would also hide treasure chests in especially dangerous locations.)
The map had a start and a destination. Usually, this was something like 'home' and 'school'. Because I was an extremely inventive brat. You would thus also have a backpack, that I would fill with whatever I thought of, and have a little list of stuff.
In one memorable play (maybe the first) I also had a (cleaned) ....whatever you call that little popper that goes in chickens and pops up when they hit the right temperature? That was used as a main piece because it was fun to make it bounce up and down like a pogo stick.
Once the prep had been done, you just had to, uh, rope in the nearest adult and have them tell you what they wanted to do, while you use your logic to decide if it works or not. No dice, no character sheets, just a small dictator of a DM.
It didn't go over too badly all things told, AKA they didn't seem to be in too much pain. And I would evolve it a bit, by getting a notebook and having kids in my class (way later) write on the next page their actions, pass the book back, write the response, and so on and so forth.
I dunno exactly when I found out about the real thing and was like, 'Oh, gdi' but I did.
I feel like I should mass-produce some maps and maybe inventories and sell it as an activity book for the kids of tabletop gamers.
(My first experience with actual tabletop was finding a discounted book that claimed to be a game! Cool, my antisocial self is thrilled, I wonder how it'll work? Answer: By having friends. I was crushed and while I read through some of it, Changeling would sit on my shelf, exiled, for years.)
I wrote a fingerprint-scanning home button on the iphone before one existed, lol