dircproxy is an IRC proxy server ("bouncer") designed for people who use IRC from lots of different workstations or clients, but wish to remain connected and see what they missed while they were away. You connect to IRC through dircproxy, and it keeps you connected to the server, even after you detach your client from it. While you're detached, it logs channel and private messages as well as important events, and when you reattach it'll download those logs to you using ordinary IRC protocol.
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).
The DNEWS News Server is a (USENET) news server. Installing your own local news server software gives you complete control to create your own discussion forums for communication. DNews News Server software provides many features, including ease-of-use, reliability, and scalability.
DooM Legacy is an enhanced port of Doom, the classic first-person shooter from iD Software. It features high screen resolutions, an OpenGL renderer, fullscreen modes under X, client-server architecture for up to 32 players on IP-networks, Quake-style keybindings, a console, and more. It is available for Linux, DOS, and Win32.
dopewars is a UNIX rewrite of the MS-DOS program of the same name, which in turn was inspired by John E. Dell's "Drug Wars" game. You have one month to buy and sell drugs on the streets of New York, the aim being first to pay off your debt to the loan shark and then to make a fortune. And if you have to shoot a few cops in the process, well... The game includes TCP networking allowing you to meet (and shoot) other human drug dealers. Computer drug dealers are currently in development.
Dr. Geo is an interactive geometry program that is distributed as a universal portable application. It allows one to create a geometric sketch and manipulate it according to its constraints. It is usable at home or at school, in primary or secondary education. It is simple and effective with extended features including scripting and programming.