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.
0verkill is a client-server 2D deathmatch-like game in ASCII art. It supports free connecting/disconnecting during the game, and runs well on modem lines. Graphics are in 16-color ASCII art with elaborate hero animations. 0verkill features 4 different weapons, grenades, invisibility, and armor. The package also contains reaperbot clients, a simple graphics editor, and a level editor.
PhysicsFS is a library to provide abstract access to various archives. The programmer defines a "write directory" on the physical filesystem. No file writing done through the PhysicsFS API can leave that write directory, for security. For file reading, the programmer lists directories and archives that form a "search path". Once the search path is defined, it becomes a single, transparent, hierarchical filesystem. This makes for easy access to ZIP files in the same way as you access a file directly on the disk, and it makes it easy to ship a new archive that will override a previous archive on a per-file basis. Symbolic links can be disabled, for added safety. Finally, PhysicsFS gives you a platform- abstracted means to determine if CD-ROMs are available, the user's home directory, where in the real filesystem your program is running, etc.
Lincity is an SVGALIB (Linux only) and X based city/country simulation game for Linux and other Unix platforms (Solaris, FreeBSD, HP_UX, AIX, SCO and IRIX). There is also a Win32 version (win95 and NT) available as a separate package. The game reminds a bit of SimCity but has it's own goals and methods to get there.
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.
JamochaMUD offers Unicode, plug-in, and multi-language support (8 different languages) to allow a more enjoyable MUCKing/MUDding experience. It features command history, synchronized window controls, experimental SOCKS 5 support, and greatly improved ANSI colour support. It plays nice on Unix systems, supports a wide range of MU*s, and also includes emulation of some TinyFugue editor controls. JamochaMUD includes classes that may be easily reused in other Java applications.
DeuTex is a wad composer for Doom, Heretic, Hexen and Strife. It can be used to extract the lumps of a wad and save them as individual files. Conversely, it can also build a wad from separate files. When extracting a lump to a file, it does not just copy the raw data, it converts it to an appropriate format (such as PPM for graphics, .au for samples, etc.). When it reads files for inclusion in pwads, it does the necessary reciprocal conversions. In addition, DeuTex has functions such as merging wads, etc.