Both for simple game dev, but also because the popular XMPP server Prosody is written in lua and I am interested in developing extensions for it.
It seems fairly popular around here as well, especially in the form of Love2D: https://love2d.org
So if you want to help me or just join me in learning it, this is the place. Although a word of warning... I am probably going to be a lot slower than you as I suck

I'll probably start with this tutorial series: https://sheepolution.com/learn/book/contents
Maybe something from here is interesting as well: http://lua-users.org/wiki/TutorialDirectory
But the medium term goal is to revive this Love2D project and get it to a fun state:
https://github.com/poVoq/opencrypt
https://www.youtube.com/watch?v=_xzpXc8emBE
Or maybe I'll try some Godot project with this: https://github.com/perbone/luascript