YouTomb is an MIT Free Culture project that chronicles videos which have been removed from YouTube for alleged copyright violation. Unfortunately, YouTube's enforcement system squeezes out a lot of expression that would probably fall in the legal, "fair use" category. In MIT-FC's own words:
When a user-submitted video is suspected to infringe copyright, the rights holder is contacted and given the option to take down the video in question. In addition, rights holders can submit DMCA takedown notifications at any time that cause YouTube to immediately remove alleged infringing content.
MIT Free Culture became especially interested in the issue after YouTube announced that it would begin using filtering technology to scan users' video and audio for near-matches with copyrighted material. While automating the takedown process may make enforcement easier, it also means that content falling under fair-use exceptions and even totally innocuous videos may receive some of the collateral damage.
As YouTube is not very transparent with the details surrounding this process and the software used, YouTomb was conceived to shed light on YouTube's practices, to educate the general public on the relevant copyright issues, and to provide helpful resources to users who have had their videos wrongfully taken down.
The site doesn't actually cache full videos, but it retains screenshots and metadata. The video depicted below appears to be a Rick Roll of Ronald McDonald. This would definitely pass as fair use in my book.
(Thanks for the link, Harley!)