AA-lib is a low level gfx library just as many other libraries are. The main difference is that AA-lib does not require graphics device. In fact, there is no graphical output possible. AA-lib replaces those old-fashioned output methods with a powerful ASCII art renderer. The API is designed to be similar to other graphics libraries.
Allegro is a multi-platform game library for C/C++ developers that provides many functions for graphics, sounds, player input (keyboard, mouse, and joystick), and timers. It also provides fixed and floating point mathematical functions, 3D functions, file management functions, compressed datafile, and a GUI.
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.
Bomber Instinct is a multiplayer-only bomberman-like game which adds many features (such as special powers for the characters). Basically, several people must battle in a maze, their only weapon being a bomb which explodes, throwing flames vertically and horizontally. The game only plays on a single computer for now.
Circus Linux! is a clone of the Atari 2600 game "Circus Atari." The object is to move a teeter-totter back and forth across the screen to bounce clowns up into the air. When they reach the top, they pop rows of balloons and then fall back down. If you don't catch one, you lose a clown.
CFL (Compressed File Library) is meant for the save-files used by games, and other sorts of data files. Its features include pluggable class factories, easy CFL file creation at runtime, and the ability to have multiple separate CFL objects in memory at the same time. The package also includes a CFL testing tool to make it easier to port the library and to create additional plug-in compressors, preprocessors, and ciphers. It also includes a makecfl utility, which makes it easy to create ini files.