Calling your website "the Internet Archive" seems a bit pretentious, but it's not hubris behind the San Francisco-based nonprofit digital library. It's a desire to provide free "universal access to all knowledge" and so far, archive.org has done a bang-up job. It has catalogued "collections of digitized materials, including websites, music, moving images and nearly 3 million public-domain books," according to its Wikipedia page (which is, in all likelihood, archived).
Here is a list of just some of the items available at archive.org: bootleg audio from Grateful Dead performances; films like Night of the Living Dead (1968) and The Ghoul (1933), starring Boris Karloff; more than 10,000 audiobooks like Carl von Clausewitz's On War, Arthur Conan Doyle's The Adventures of Sherlock Holmes and Edgar Rice Burroughs' The Gods of Mars; and video games from the glory days such as "Prince of Persia," "The Oregon Trail Deluxe," "Wolfenstein 3D" and "Metal Gear." It's all free to access, organized into Video, Audio, Text (eBooks) and Software, and subcategorized into collections containing everything from old commercials and NASA educational videos to fractal screensavers.
If you're looking for a particular piece of media in the public domain, chances are good it's somewhere in the Archive: As of October 2012, it was 10 petabytes in size (yes, that's 1 million gigabytes).