I'm about break even on a learning project for me: https://chrono.quest -- until you factor in my dev/user support time lol

It's a bite-sized daily history game, much inspired by Wordle.

Why do it?

Every once in a while someone emails about how they play it with their friends or family every day and it helps them keep in touch.

Also, as a data engineer, I wanted to understand more of what goes into deploying a consumer web app. Turns out I much prefer crunching data :)