DansGuardian is a Web content filtering proxy that uses Squid to do all the fetching. It filters using multiple methods including, but not limited to, phrase matching, file extension matching, MIME type matching, PICS filtering, and URL/domain blocking. It has the ability to switch off filtering by certain criteria including username, domain name, source IP, etc. The configurable logging produces a log in an easy to read format. It has the option to only log text-based pages, thus significantly reducing redundant information (such as every image on a page).
dagrab is a command line driven tool for extracting digital audio from cd. It works great with IDE drives (and others type too if the kernel supports digital audio read for them, I think this does not include SCSI drives for now), and supports jitter correction, filters and audio post-processing,as well as CDDB to automatically name your files appropriately.
daemon turns other processes into daemons. There are many tedious tasks that need to be performed to correctly set up a daemon process; daemon performs these tasks for other processes. This is useful for writing daemons in languages other than C, C++, or Perl (e.g. sh, Java). If you want to write daemons in languages that can link against C functions (e.g. C, C++), see libslack, which contains the core functionality of daemon.
D1X is a modification of the Descent 1 source that was released by Parallax. It's mostly compatible with Descent 1 v1.5, both in multiplayer (new features/fixes may not work with standard Descent, but d1x will still work fine using the old methods) and on the local machine. D1x combines code from both D1DJGPP and ldescent (which are both now defunct/assimilated into d1x) and adds many features of its own. D1x runs on Linux (SDL, SDLGL, GGI, svgalib, and GLX), DOS, and Windows (WGL, DirectX, and Direct3D (incomplete)). In software mode, optimized renderers are available for Pentium and PPro/P2 computers, and OpenGL hardware acceleration is also available.