Heh, maybe you'll get a kick out of
http://nand2tetris.org/ (if you haven't come across it already). I finally finished part 1 of the course (implementing the Hack machine) and it was one of the best and most challenging learning experiences I've ever had. My plan is to do part 2 (VM, high level language, OS) with Lisp instead of the language they implement. That's
been the plan for the last 6 months, anyway...