BZFlag is a 3D, multiplayer, tank battle zone, capture the flag game that pits players against each other in a networked environment. It runs on Windows 95/98/NT/2000, Linux, MacOS 10.x, Irix, Solaris, and others. An OpenGL accelerator is highly recommended, but it is playable with 3D in software.
You are captain of the cargo ship Chromium B.S.U., responsible for delivering supplies to our troops on the front line. Your ship has a small fleet of robotic fighters which you control from the relative safety of the Chromium vessel. Chromium B.S.U. is a fast paced, arcade-style, top-scrolling shooter. It uses OpenGL for graphics, OpenAL/SDL_mixer for sound effects, GLC/FTGL for text rendering, and glpng/SDL_image for texture loading.
gGo is a Go board, SGF editor, client for the Internet Go Server, and an interface for playing with GNU Go. gGo is written in Java and available for Linux, OS X, OS/2 and Windows. gGo is distributed free of charge. Go is an ancient boardgame, very common in Japan, China, and Korea.
SecureSkat is a peer-to-peer implementation of the German card game Skat. The program negotiates participating players and game sessions over an arbitrary IRC network (Internet Relay Chat). Neither a trusted third-party (dealer) nor a centralized game server is necessary. All critical operations, e.g. shuffle of the deck, are performed using advanced cryptographic techniques (so-called Mental Poker solutions) provided by LibTMCG. The outdated OpenSkat branch contains a graphical user interface based on XSkat 3.4. This interface can be used with most recent versions, but must be built separately.
Globulation is an innovative high quality real-time strategy which minimizes micro-management by automatically assigning tasks to the units. The player has to choose the number of units they want for the different tasks, and the units will do their best to satisfy the requests. This allows the player to manage more units and to focus on the strategy.
X-Plane is a flight simulator that reads in the geometric shape of any aircraft and then figures out how that aircraft will fly. It does this via an engineering process called "blade element theory", which involves breaking the aircraft down into many small elements and then finding the forces on each little element many times per second. These forces are then converted into accelerations, which are then integrated to velocities and positions. This gives X-Plane the most realistic flight model available for personal computers.
The Mana World (TMW) is a serious effort to create an innovative free and open source MMORPG. It uses 2D graphics and aims to create a large and diverse interactive world. The game aims to be a unique place for people to interact not only by fighting each other but to play life, form a community within the community, or just simply chat. Although the game is never-ending and a linear story cannot be applied, it should have enough background to describe and predefine tribes, kingdoms, and the environment overall. Fullfilled quests should lead to certain events depending on them being solved. Quests should also encourage teamwork.