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.
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.
Halyard is a scriptable multimedia engine with support for video, audio, graphics, and user interaction. It currently runs on Windows, and has a preliminary Macintosh port. It is based on PLT Scheme, wxWidgets, and the Quake 2 Engine. It includes a rudimentary IDE based on Scintilla.
HopSlide is a tool for authoring and playing slides. It supports animations, annotations (slide overlays), math formulas (MathML support and TeX syntax support), SVG images, and canvas graphical effects. HopSlide can be used to compile slides into XHTML files. These files can be used by XHTML capable browsers (e.g., Firefox). Compiled slide files can be used to play the slides without HopSlide.
Net-Fu is a DHTML implementation of the classic GIMP NET-FU interface. It uses the GNU Image Manipulation Program and Xvfb to produce a wide variety of royalty-free custom and semi-custom graphics, logos, and clip art of various sorts. You simply select a style of logo from such choices as "neon", "chrome", and "crystal", specify parameters such as text string, typeface, size, and colors, and your logo is returned without further ado.