Soulseek (http://www.slsknet.org) is a communication and file-sharing system. It is quite similar to Napster: it lets you exchange files, search for files, chat with other users in public and in private, browse their files, and get recommendations for music. SoulSeek for Linux is a GUI client for the system written in Python/wxPython. It includes all the major functionality: chat, searches, and file transfers.
Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
Xvid (formerly XviD) is an open source MPEG-4 video codec, implementing MPEG-4 Simple Profile, Advanced Simple Profile, and Advanced Video Coding standards. It is written in C with assembler optimizations for quality and speed (including MMX, SSE, and 3Dnow! code for i386 and AltiVec for PowerPC), and is especially optimized towards offline, multi-pass compression for storage and archival purposes.
Linux Security Auditing Tool (LSAT) is a post install security auditing tool. It is modular in design, so new features can be added quickly. It checks many system configurations and local network settings on the system for common security/config errors and for packages that are not needed. It has been tested on Linux (Gentoo, Red Hat, Debian, etc.) and Solaris (SunOS 2.x).
tk500 is a multiplatform programming and cloning utility for the portable Yaesu VR-500 receiver. It can read the memory image from the radio, display the information graphically, and save it to a file. It can import information from an RT Systems .RDF file and export memory channel information to a .CSV (comma-separated values) file. Users are free to change most settings and write the memory image back to the receiver. tk500 exploits undocumented features within the radio.
Speex is a patent-free compression format designed especially for speech. It is specialized for voice communications at low bit-rates in the 2-45 kbps range. Possible applications include Voice over IP (VoIP), Internet audio streaming, audio books, and archiving of speech data (e.g. voice mail).
WvStreams is a library set composed of a number of parts. Among them are WvIPStreams (WvTCPStream and WvUDPStream), WvStrings (yet another C++ String class), WvCrypto Streams (including an easy way to add SSL support to applications), UniConf (a universal configuration system), WvLog (nice, simple handling of log files), and a whole host of other goodness. These are the base classes used to build programs such as the ever popular WvDial, TunnelVision, FastForward, KWvDial, and retchmail.
OpenVPN is a robust and highly configurable VPN (Virtual Private Network) daemon which can be used to securely link two or more private networks using an encrypted tunnel over the Internet. OpenVPN's principal strengths include wide cross-platform portability, excellent stability, support for dynamic IP addresses and NAT, adaptive link compression, single TCP/UDP port usage, a modular design that offloads most crypto tasks to the OpenSSL library, and relatively easy installation that in most cases doesn't require a special kernel module.
jcinc is an emulator for the Bell Lab's CARDIAC (Cardboard Illustrative Aid to Computation) computer. A CARDIAC assembler (casm) is included. The CARDIAC kit was published in 1969 to teach the internal workings of a digital computer and machine code programming. jcinc emulates the CARDIAC computer and allows the user to run CARDIAC programs.