Mezzano – An operating system written in Common Lisp
There are still people explaining to me why you need a 'system programming language' like C or Rust for certain tasks.  Meanwhile, I'm playing a game of Quake on Mezzano, where everything from drivers to the actual videogame is written in pure Common Lisp.In case you wonder how froggey managed to obtain a Common Lisp version of Quake, have a look at https://github.com/froggey/Iota.