Movitz was neat back in the day (last update 2008): http://common-lisp.net/project/movitz/ http://common-lisp.net/project/movitz/ That's a one man effort to wr

Movitz was neat back in the day (last update 2008): http://common-lisp.net/project/movitz/ http://common-lisp.net/project/movitz/ That's a one man effort to write a Lisp OS for x86 from scratch. He wrote his own compiler, basically with the chain of macroexpansions bottoming out in WITH-INLINE-ASSEMBLER. I only played with it once. I was struck by how cool it was that I could play with the Lisp REPL from inside the garbage collector (also written in Lisp). This was surprising but then seemed obvious: the GC is simply a Lisp function that's moving objects from old-space into new-space (and then deleting old-space), and it doesn't mind if you wake up and interleave a few more allocations into new-space. Movitz was current back in 2004 when Pascal Costanza organized the first real european Lisp workshop in Oslo and a whole bunch of Lisp hackers who only knew each other through the 'net got to meet up in person. fun times.