Big Huge Labs Writer - Writer is a free online distraction free writing environment provided by Big Huge Labs.
MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
Scribes - A text editor for GNOME that combines simplicity with power.
projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.
Caret - Better Markdown Editor for Mac / Windows / Linux
Magic Music Visuals - Fully-customizable and highly responsive visuals for live and recorded audio & MIDI.