2·6 hours ago- The Jepsen project, which performs heavy testing of distributed database engines, and often finds bugs, is written in Clojure: https://jepsen.io/
- The Maxima computer algebra software is in Common Lisp
- The ITA flight fare search and pricing system is in Common Lisp
- and my beloved tiling window manager, stumpwm, is also written in Common Lisp