LispOS Project
Goal: reflective OS based on LISP. Mostly merged with TUNES. No code, but many ideas politely presented in a fascinating archived mail list. Mail list archives.
TUNES Project
Open source resource for learning about programming languages and operating systems. Led by French OS philosopher Fare'. Some 2,000 links.
Ultra Programming Language Project
Goal: create an advanced open source language and compiler. Interesting mail archives. Allied with TUNES.
UniOS: A Concept OS
Merging with TUNES. Some useful ideas with very clear, well written explanations, and links. No code.