Visual Beat - Interactive music video
Figure - Propellerhead creates world-class software products and services that inspire music makers and provide the foundation for a worldwide creative musical community.
The Lucid Realm - Listen to music in 3D
SoundGrail - SoundGrail Music App designed for pianists, guitarists, and DJs.
Google Music Lab - Interactive experiments that use the Web Audio API
keezy - A colorful soundboard. Play with music.