ioquake3 (or ioq3 for short) builds upon id Software's Quake 3 source code release. It cleans it up, fixes bugs, and adds features. Its goal is to be the Quake 3 distribution upon which people base their games and projects. Its design goals include optimizing the engine for playing Quake 3: Arena, Team Arena, and all popular mods. This distribution of the engine has been ported to many new platforms. While it doesn't have PunkBuster (and never will), it does provide more security for servers and clients by way of various bugfixes which aren't in id's client.
swampex (or Swamp Explorer) is a cross-platform library designed to work with raster maps in Ozi Explorer format. Using this library, you'll be able to collect maps in the file system, get information about map calibration, find maps by latitude/longitude, render maps in SDL surfaces, and more.
Punto is a tool for plotting particles. It reads particle data from a file and displays them in a window in several ways, like dots, circles, squares, and spheres. It can also plot vectorial fields. The output can be in one, two, or three dimensions. It is possible to zoom in and out, rotate in three dimensions, draw periodic images, and more. It can produce animations easily from your data files.
Tric-Tac-Toe is a new twist (or perhaps "tilt") on the classic Tic-Tac-Toe game. The board resembles a Rubik's Cube surface; three players each take turns filling up the surface of the board. Once the board is full, a winner is declared according to the point totals of each player. The "tric"ky part is the connections on the board that score points.