So looking around for some cool clips to play with and I found a few great links online, so figured I would share them here. Of them all, Beeple seems to be the coolest, and they include Cinema 4D files as well if you want to play.
Almost all videos have open licenses (creative commons, public domain etc.) but be careful and read the License box before you use them!
1) Archive.org – Prelinger & Ephemeral
The Prelinger collection: http://www.archive.org/details/prelinger has a lot of 50′s and 60s commercials and documentaries. Another great library is the Ephemeral: http://www.archive.org/details/ephemera, with mostly old educational videos.
A really nice source of VJ loops, ultra modern and very cool http://www.beeple-crap.com/vjclips.php
Really cool videos from the past at http://www.avgeeks.com/
4) U.S. Department of Energy Historical Test Films
A nice collection about experiments with nuclear bombs http://www.nv.doe.gov/library/films/testfilms.aspx
Videpong is a community of VJs who upload their Creative Commons loops http://www.videopong.net/