Cleese is a project to build a functioning operating system written almost entirely in Python. The basic idea is to have a microkernel mostly based on the Python VM and all other operating system functionality written in Python.
With Dave Long, I successfully built a proof-of-concept back in 2003.
In February 2007, I moved Cleese from SourceForge to Google Code Project Hosting and then in October 2009 to GitHub at https://github.com/jtauber/cleese/
The original post was in the category: python but I'm still in the process of migrating categories over.