I’ll start. I have recently gotten into 3D printing, and, while incredibly frustrating sometimes, there’s nothing more rewarding than getting a perfect print.
Role-playing games. It might hit close to mainstream now - those tv series and movies where they appear directly or indirectly, certainly made the hobby more famous - but as an actual hobby, it’s still a niche thing.
I think they should be part of educational program, globally.
Tabletop role-playing games in general. D&D and Pathfinder are now the most widely recognized and played ones, but there’s whole library of alternatives. Thousands of games out there, catering to different needs, offering different experience, set in different worlds and offering different choices.
For example, there’s BLUE PLANET in production - a SF/cyberpunk/environmentalist game in production, taking place on a distant planet covered mostly by water. In terms of the setting, it’s antithesis to DUNE, or very old, but stil amazing DARKSUN but the undertones are similar - people fighting against greed that ruins their world.
Whatever idea you have, zombie apocalypse, kids saving the world, people investigating Lovecraftian horror, spaceships, weird west world, clash of fantasy kingdoms - there’s a game for that.
I second with Vampire: The Masquerade, The Dark Eye, Shadowrun and StarWars RPG in my family. Teach your kids to play and they will never have time or money to waste on drugs. ;)