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.
GnuCash allows you to track bank accounts, stocks, income, and expenses. As quick and intuitive to use as a checkbook register, it is based on professional accounting principles to ensure balanced books and accurate reports. It is backed by an active development community and is blossoming into a full-fledged accounting system.
Beast is a powerful music composition and modular synthesis application. It offers multiple input methods like multitrack, piano roll, and pattern editing and supports skins. On the technical side, it has a wide range of abilities like sequencing, unlimited undo/redo history, real-time synthesis with multiprocessor support, full duplex 32-bit audio rendering, precise timing down to sample granularity, on demand loading of partial wave files, on the fly decoding of various sample formats, aliasing free oscillators, and full Scheme scripting support.
AutoGen is a tool designed for generating program files that contain repetitive text with varied substitutions. Its goal is to simplify the maintenance of programs that contain large amounts of repetitious text. This is especially valuable if there are several blocks of such text that must be kept synchronized. Output is specified with a Scheme-enhanced output template. Input, if required by your template, may come from AutoGen definitions, CGI data, or XML files.
Bigloo is an implementation of the Scheme programming language. It relies on an optimizing compiler from Scheme to C. Bigloo enables connections between Scheme code and C code. It proposes many extensions to Scheme such as a regular parser compiler, an lalr parser compiler, pattern matching, an object layer, etc.
Chicken is a Scheme compiler that translates most of R5RS Scheme into relatively portable C. It supports fully general tail-call recursion, first-class continuations, and has a very flexible and efficient interface to C and C++. Chicken implements several extensions to the Scheme language: lightweight threads, pattern matching macros, dynamic loading of compiled code, and various object-oriented paradigms, such as TinyCLOS, and others. The library system includes hundreds of convenient modules for practical use.
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.