GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
GLAME (GNU/Linux Audio Mechanics) is meant to be the GIMP of audio processing. It is designed to be a powerful, fast, stable, and easily extensible sound editor for Linux and compatible systems. It has full support for non-destructive editing including undo/redo and applying LADSPA effects. Its supported platforms are Linux, BSD, IRIX, and OS X. It uses guile and libxml, and the GNOME libs available is highly recommended. MP3 and Ogg files can be processed if libmad and libvorbisfile are installed.
Siag Office is a free office package which consists of the spreadsheet Siag, the word processor PW, the animation program Egon, the text editor XedPlus, the file manager Xfiler and the previewer Gvu. Siag is easy to use, yet infinitely flexible through multiple embedded interpreters and a plugin mechanism that allows other programs to run inside the main document. The supported interpreters are SIOD, Guile, Tcl, and Python.
Junkie is a real-time packet sniffer and analyzer. It is modular enough to accomplish many different tasks. It can be a helpful companion to the modern network administrator and analyst. Compared to previously available tools, junkie lies in between tcpdump and wireshark. Unlike tcpdump, its purpose is to parse protocols of any depth; unlike wireshark, though, it is designed to analyze traffic in real-time and so cannot parse traffic as exhaustively as wireshark does. In addition, its design encompasses extendability and speed. It has a plug-in system and high-level extension language that eases the development and combination of new functionalities; threaded packet capture and analysis for handling of high bandwidth networks; and a modular architecture to ease the addition of any protocol layer. It is based on libpcap for portability, and well-tested on professional settings.
Thousand Parsec is a turn-based space empire building game, as well as a framework for creating a similar group of games, which are often called 4X games (eXplore, eXpand, eXploit, and eXterminate). Some examples of games from which Thousand Parsec draws ideas are Reach for the Stars, Stars!, VGA Planets, Master of Orion, and Galactic Civilizations. Unlike commercial alternatives, it is designed for long games supporting universes as large as your computer can handle. It allows a high degree of player customization, and features a flexible technology system where new technologies may be introduced mid-game.
mu is a collection of utilities for maildirs, in particular for indexing and searching them. mu fills a database with information about your emails, which can then be queried using an easy query language. It can work stand-alone or be integrated with a mail client. It also provides an emacs-based email client ("mu4e") and bindings for Guile/Scheme.
MIT/GNU Scheme is an implementation of the Scheme programming language, providing an interpreter, compiler, source-code debugger, integrated Emacs-like editor, and a large runtime library. MIT/GNU Scheme is best suited to programming large applications with a rapid development cycle. Recent versions of the system are supported on the following platforms: GNU/Linux, *BSD, OS/2, and Windows.