Answer by Richard Muller:
I sat in on the lectures of Prof. Ken Jowitt for a semester. I did this because I was fascinated with his theories on political science, but I was also curious about the rumor I had heard that at the end of each lecture, all 500 of his students applauded and gave him a standing ovation.
It turned out to be true, and I joined them. Each of his lectures was a work of art. I learned an amazing amount about teaching by attending those lectures.
I have had one professor, a very famous one, attend all my lectures in my "Physics for Future Presidents" class. I was very flattered, and yet remarkably uncomfortable. Here was someone who could tell if I was bamboozling the students. It was a very good discipline for me. (You can watch my lectures for 2006 on YouTube.)
I have advised professors who have poor teaching records that one of the best things they can do is go to the lectures of those who win the "Distinguished Teaching Award." Anyone can improve their lectures, but the best way to do that is to see how the great teachers really teach.