Plot: GLtron is a 3D snake game based on the light cycle portion of the film Tron. The game is free and open-source software and has been ported to many mobile and non-mobile operating systems such as Windows, MacOS, Symbian and Android over the years. Wikipedia
Plot: Liquid War is an open source multi-player action game based on particle flow mechanic. Thomas Colcombet developed the core concept and the original shortest path algorithm, the software was programmed by Christian Mauduit. Liquid War 6 is a GNU package distributed as free software and part of the GNU...
Plot: Chromium B.S.U. is an arcade-style, top-scrolling space shooter available on Windows, iPhone, PSP, Mac, AmigaOS 4, Linux and numerous other UNIX-like operating systems. It is a free software distributed under the Clarified Artistic License. Wikipedia
Plot: Tenés Empanadas Graciela is a turn-based strategy game distributed by several popular Linux distributions. The idea for this free and open-source software program came from the board game TEG, which itself is based on the popular Risk game but differs in many aspects of the rules. Wikipedia