I could name so many tabletop RPGs for this. Unfortunately, since Hasbro has dominated the space like a generational pile of elephant dung for over 2 decades now, and TSR actually did manage to make a few smart marketing decisions before Dragon Dice and the bankruptcy, I guess I can't be too shocked.

So I guess I'll go with a board game. Tsuro - The Game of the Path. It's super-simple to learn and play, can be interesting for kids and adults alike, and it's just a really solid, fun, game. There's even an iOS version. I don't understand why it's a niche game instead of being front-and-center ahead of Monopoly or Clue(do). It's not even prohibitively expensive, honestly - the wholly valid argument against Carcassonne and other niche games. There's no good reason I can think of why Ticket to Ride is more popular than Tsuro.