Daniel Herring wanted me to
mention read-macros. It's
not asdf-installable, is barely documented, doesn't include any
version information, and uses a weird (for Lisp) license. Enjoy!
Alexander Lehmann created some highly
tutorials about writing a ray tracer in Common Lisp. I love to see
people doing stuff like this, but personally rarely find the time to
actually sit down and watch them, which is frustrating. Alexander has created over five
hours of Lisp tutorial material, so even if I don't find the time
to watch it, you should.