The Complete Roguelike Tutorial

is an annual community event hosted at /r/roguelikedev

Where people follow along with the roguelike tutorial hosted at

That tutorial is for the libtcod library and uses Python, but you can use different tools if you wish (someone is doing it in x86-64 assembly this year), and it looks like a lot of people take the opportunity to work on their own roguelike projects not directly related to the tutorial. Like a knitting circle with a mix of beginners following a pattern and more experienced people with advanced projects. And lots of dungeon looting.

In any case I am going to follow the tutorial, but with Chicken Scheme and its bindings for SDL2.