After almost 15 years, I've recently been diving into #WorldOfWarcraft server emulation again and it's still pretty interesting. In particular, reading about all the formats on https://wowdev.wiki is much more interesting now that I actually understand everything.
This community (in particular the German forum darkwow.de) is what got me into programming initially, so I'm delighted to see it's still alive and well. Bonus nostalgia that it's all #WotLK focused.