Windows XP Open-Source
What? Well, we all know that this will never happen in our lifetime. As most know, the end of life for Windows XP is quickly approaching. June 30, 2008 is the end of XP as we know it today. Vista will rule until Windows 7 is released in 2010.
Back to Windows XP Open-Source, I just became aware of the ReactOS Project (I must be living under a technology rock or something). React is an open-source Microsoft Windows XP-compatible operating system. Nice!
The project is still in the alpha stage, but it certainly looks promising in its current state of development. Checkout the product roadmap and screenshots for more details. The React project officially started in 1998 and see it has been a challenge to date.
Good luck to the development team and contributors.