Music Video Genome
lets you watch music videos like you listen to Pandora. Built on the API of the video sharing site VHX.tv, it integrates Last.fm and YouTube, so you can pick an artist and stream a sequence of related music videos.
I called it Genome because it's not that simple to match music videos to real songs. Most music "videos" on YouTube are just a stupid static image. Granted not all songs have music videos, but it would be amazing if I could crowd-source the documentation of music videos to songs. If a song does not have an official music video, fans could make their own and have it bubble up as the official video.
Right now, you can click a box when a fake music video comes up and even suggest an alternative. The selection is still as spotty as an average YouTube search result, but I fear this site could eventually become incredibly addictive.