Android, DOS, FirefoxOS, Linux, MacOS and Windows all in one..
Sensa is not an operating system, is a work environment compatible with Android © 4.4.4, Firefox OS ©, Linux Ubuntu 12.12 ©, MacOS Classic 7 ©, MS -DOS © operating systems, and Microsoft Windows 8.1 ©; whose distribution is free, and with source code available under GNU GPL 2.0 license .
Latronix Regnum Arts - Open Source Faction is an open source and freeware developer for all sorts of goodies. Be it games or applications. This is the home for the Drug Turfs Game (A Drug Wars like game) and the Drug Turfs Library.
The Periodic Tables Package is an advanced suite of applications for both Windows and Linux that allow chemists and students alike to use the Periodic Table on their computers.