I'd like to start a discussion about pushing the boundaries of rock music and what bands have done that, and how. I have to prepare a lecture for a class on this topic because I don't want to do a 20 page term paper and my professor likes me enough to have me do this kind of alternative. She wants to start at Radiohead, but everytime I sit down and try to come up with some kind of backbone to the lecture I can't come up with much. Any ideas?