Tennix! is a tennis game written in C using the Simple DirectMedia Layer. The game features a two-player game mode and a single-player mode against the computer.
The Tennix source code is available under the GNU General Public License, Version 2 or later.
Tennix currently runs on Linux, MacOS X and Windows, but porting it to other platforms should be straightforward, if they support SDL.
These details are provided for information only. No information here is legal advice and should not be used as such.