Clone Hero - Clone Hero is a free rhythm game, which can be played with any 5 or 6 button guitar controller...

BandNext - Discover bands that sound similar to artists you already love with BandNext. A single click saves your results to a Youtube playlist.

Osu - Osu is Music, Rhythm, Single and Multiplayer video game developed by Dean Herbert.

Spotify - Map shows when two people play same song at same time

StepMania - Rhythm game for Windows, Mac, and Linux.

stats.fm - With the click of a button you'll be logged with your Spotify account and you'll instantly gain access to a valhalla of cool stats and insights.