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 .
FreeWPC is a software framework for writing new software for 1990's Bally/Williams pinball machines. The framework allows you to build your own ROM images, define your own game rules, incorporate dot matrix animations, design lamp shows, and so on.
A port of the Linux operating system kernel and assorted userspace to the Nintendo Wii.