I finally tracked down this link to a HUGE collection of videos (mp4 format) available through BitTorrent of presentations at the 22nd Chaos Communication Congress (223c) in Europe. Will need a Torrent client like Azureus. I have already started downloading this and am not even 1/4th through the list and it is already taking up 12GB of space. Will also need QuickTime or an alternative to QuickTime (recommended).

Updated link: videos. Be creative with the URL and you can find past years. When in doubt, hit the root site.