ICBM3D (Inter-Continental Ballistic Missiles, 3D) is a 3D game of defense. Like the original "Missile Command" and its clones, this game places you in control of Anti-ICBM weapons which you use to destroy an onslaught of missiles (and other nasties) which are dropping onto your nation. The game ends when your cities have all been destroyed. You only gain replacement cities by acheiving certain score thresholds during each attack. The differences between Missile Command and ICBM3D is that ICBM3D, as the name suggests, provides a 3D perspective. You take advantage of X-Window's 3-button mouse to control your firing sight in 3-dimensions and change your viewpoint.
TuxKart is a 3D GoKart racing game with several famous OpenSource mascots participating. The game uses PLIB and OpenGL, and is portable to a wide range of OS's. There are several racecourses provided, with full information on how to add your own. Except for a few minor details, this game is essentially complete, and very playable.
Neohunt is an enhanced variant of hunt, a multiplayer game in which you run around a maze and shoot your friends before they shoot you. It is also an artifact of an earlier age, to be used either as nostalgia (if you remember the eighties) or as an example of how much better things are today (if you don't).
Wine is an implementation of the Windows API on top of X and Unix. It does not require Microsoft Windows, but can use native Windows DLLs if they are available. It provides both a development toolkit for porting Windows source code to Unix as well as a program loader, allowing many unmodified Windows programs to run on x86-based Unixes.
GCompris is an educational software suite with numerous activities for children aged 2 to 10. Some of the activities are game-orientated, but nonetheless still educational. These include computer discovery (keyboard, mouse, different mouse gestures), algebra (table memory, enumeration, double entry table, mirror image), science (the canal lock, the water cycle, the submarine, electric simulation), geography (place the country on the map), games (chess, memory, connect 4, oware, sudoku), reading practice, and others (learn to tell time, puzzles of famous paintings, vector drawing, cartoon making, etc.). It currently offers in excess of 100 activities, and more are being developed.
yuxtapa is a multiplayer real-time CLI game. It looks like a roguelike, but feels like a multiplayer 1st-person shooter with a focus on team play. The idea is to take the "feel" of such team based multiplayer games as Enemy Territory into an NCurses-based game with roguelike controls. Like roguelikes, yuxtapa is lightweight but surprisingly rich under the crude surface. It features several classes from which to choose, each with a different special ability, randomly generated maps which can also be saved and reloaded, and multiple game modes or objectives.
TEG is clone of 'Plan Tactico y Estrategico de la Guerra', which is a clone of Risk, a networked multiplayer turn-based strategy game. TEG is not fully compliant with Risk; some rules are different. It has a server, a robot, a GNOME client, support for GGZ Gaming Zone, and IPv6.
Freeciv is a multiuser reimplementation for Unix/X of the famous Microprose game of Civilization. By default, the game is an improved Civ II, but this can be customized; modpacks for near-100% compatibility with Civ I and Civ II are included. Multiuser gameplay is real-time: in each turn, all human players move concurrently. The game is designed to remain fairly playable even on poor network connections. Freeciv can also be played on standalone machines, and its AI players are a good challenge for beginners. The source code comes with the server, two X clients, and non-X clients for MS Windows and Amiga. Freeciv is released under the GNU General Public License. It is maintained by an international team of coders and enthusiasts, and is easily one of the most fun and addictive network games out there.