This is interesting stuff
http://channel9.msdn.com/shows/Going+Deep/Singularity-A-research-OS-written-in-C/

http://channel9.msdn.com/shows/Going+Deep/Singularity-Revisited/

http://channel9.msdn.com/shows/Going+Deep/Singularity-III-Revenge-of-the-SIP/

http://channel9.msdn.com/shows/Going+Deep/Singularity-IV-Return-of-the-UI/