Lobste.rs

Gosh, this is almost my experience directly. Somehow managed to convince the developer of the Thieves World MUD that I, a young teenager, would love to program & contribute for the game. Then he said "do you know linux", to which I did not, and that's the day that I started to learn. That MUD experience got me my first real job (I showed my boss-to-be my CVS checkins), and some 30 years later, I'm still writing low-level C++ professionally.