MultiOS
MultiOS is (as its name suggests) an operating system which combines the power of the 4 most used OSes into one.
It is based on lubuntu, which gives it a stable base.
Out-of-the-box compatiblity for Windows, Linux and Android apps, security and compatiblity are the main goals of this project.
We are even working on implementing Mac OS X support, but at this point, it will only run command line based darwin applications.