We could continue with the idea that @KenWebb started, with a discussion for each of the video lecture.
I'm picturing a format that is closely tied to the video itself. Something like "video notes." The idea would be to carefully watch the video, and take notes yourself on the points that are made, and any questions that come up as you are watching them. Later, post selected notes and questions to the discussion. As a long term goal, the discussion could become complete enough to state all the key points in the lecture. With discussion on that thread, and digging into the ideas, a forum version of the lecture could be developed.