The FlightGear flight simulator project is an open-source, multi-platform, cooperative flight simulator development project. Source code for the entire project is available and licensed under the GNU General Public License.
The goal of the FlightGear project is to create a sophisticated flight simulator framework for use in research or academic environments, for the development and pursuit of other interesting flight simulation ideas, and as an end-user application. We are developing a sophisticated, open simulation framework that can be expanded and improved upon by anyone interested in contributing.
Toga II is a chess program, derivative of Fruit created by Thomas Gaksch. It has more chess knowledge and perhaps a better search algorithm. It is based on Fruit 2.1 and is free.
Netrek is a 16-player two-dimensional graphical real-time battle simulation with a Star Trek theme. A game is divided into two teams of 8 players (or fewer), who dogfight each other and attempt to conquer each other's planets.
OpenCity is a 3D city simulator game inspired by Free Reign and written by Duong-Khang Nguyen.
It is coded in C++ and uses OpenGL and the SDL. The latest stable release of the game is version 0.0.62 released October 22nd, 2009. The game is licensed under the GPL