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.
Tux Paint is a simple and entertaining drawing program geared towards young children. It has a simple interface, sound effects, and a cartoon character (Tux, the Linux penguin). Along with drawing brush strokes, lines and shapes, you can also enter text and place "rubber stamp" (or "sticker") images on the picture. Tux Paint is extensible, and could be useful in an educational environment (such as a grammar, elementary, or grade school). It's portable across numerous platforms, and runs well even on slower systems like the Pentium 133MHz.
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.
LinuxConsole is a live and modular Linux distribution that can be started from CD/DVD, hard disk, floppy disk, USB disk, or network card (PXE). The use of "console" in the title doesn't mean that it is started in "console" mode, but is meant to symbolize the simplicity of using it. This distribution is as simple to use as a game console: you can start applications without installing them. It is modular: there is a common base (device detection, GUI) and optional modules for multimedia, communication, and servers. The goal is having a very fast startup (less than 20 seconds), very good hardware detection, and many applications available (not just games).
The Volleyball Manager supports the planning, management, and documentation of volleyball tournaments and leagues. An automatic scheduler generates an optimized schedule, which can be freely modified. The projector and terminal module offer more transparency for participants and visitors of tournaments.
Tiled is a general purpose tile map editor. It's built to be easy to use, yet it is capable of catering to a host of varying game engines, whether your game is an RPG, platformer, or Breakout clone. Tiled supports plugins to read and write map formats other than its own map format.
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.