Magic Music Visuals - Fully-customizable and highly responsive visuals for live and recorded audio & MIDI.
Piano Visualizer - Bring your piano music to life with this application.
MilkDrop - 3D audio visualization plugin, compatible with WinAmp plugin API
Lifeblood Live Wallpaper - Float along in a stylized real-time 3D vein full of red blood cells!
projectM - projectM is an LGPL'ed reimplementation of Milkdrop under OpenGL.
Piano Connect - Piano Connect is one of the most popular piano learning apps that helps you play piano on your smartphone anywhere at any time.