So far I’ve come across two camps that make some of their material available on-line.
Georgetown Debate Seminar 2015: gds15.wikispaces.com
Substitute 12/13/14/ for the 15 to get previous years. Most of the 2015 material seems to be docx and pptx files, though some of the previous camps will have videos of some of the lectures. (For the older camps, the topic-specific lectures won’t matter, but the other ones on CX theory/practice will be.)
Emory National Debate Institute: endi2015.wikispaces.com/home
Substitute 2013/2014 for previous years. Many of the links on the left side of the page lead to videos of the camp lectures. As above, topic-specific lectures for earlier camps won’t matter, but the general CX lectures will. I haven’t compared previous to current videos to see if there are any differences in the general lectures.
More resources (from what seems to be a majority of the camps around) can be found at: Open Evidence Project
More videos (including some of the ones from Georgetown and Emory) can be found at: Open Video Project
(Credit goes to stock-issues.tumblr.com for a repost that led me to these.)