A decade ago I ran several “seven hour roguelikes”, https://web.archive.org/web/20160321153532/http://people.cla... is the documentation from the first one.

The first year I spent six hours writing one of the first ecs crates in Rust and then an hour turning it into a game. lots of fun! you can search “7HRL” on github to find the historical participants not too ashamed to publicize their code at the end. A few dozen people enjoyed this.