distributed.net is a loosely knit group of computer users from all of the world that is taking up challenges requiring lots of computing power (most notably the RC5, DES, and OGR cracking contests). It is simple to participate in the challenges by downloading and running their client software (which uses idle CPU time to complete its tasks).
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.
Frodo is a free, portable C64 emulator. It focuses on the exact reproduction of graphical effects possible on the C64, and comes in three "flavors" (Frodo, Frodo PC, and Frodo SC) with increasingly higher quality of emulation, but at the cost of higher processing power requirements. Frodo has been ported to a number of systems, including handheld computers. The Unix version can use either SDL, X11, or SVGAlib to display the graphics.
Open Simp-X is a powerful Internet platform for everyone, attempting to change programming for the Internet with sharing database information. It strives for scalablility, reliability, and ease of use. The platform consists of a client/server pair. Security is a top priority, and data transfers are encrypted. Open Simp-X achieves scalability through plugins. Plugins can collect information, manipulate it, and send it back to the database. Writing plugins is easy since they do not have to worry about how to send or receive their information, and can focus on manipulating it. Open Simp-X can be set up to retreive data through a LAN or through a Web server.
Tow Bowl Tactics is a game based on Games Workshop's Blood Bowl. It is an epic conflict between two teams of heavily-armed and quite insane warriors. Players pass, throw, or run with the ball, attempting to get it to the End Zone at the end of the field to score a touchdown. Games are full of violence and carnage and could be compared to a combination of Warhammer, American football, and rugby.
Vectoroids is based on the X-Window PDA game 'Agendaroids,' but uses libSDL for graphics, sound, and input, and includes nicer graphics, sound effects, and music. The objective is to survive wave after wave of giant rocks, which you must shoot to break into smaller pieces, until they are completely destroyed.