Give a clear signal when some specified proportion of students say "I don't get it"
I love the "I don't get it graph" in principle but in practice does not work for me. I use LC on my iPad while projecting keynote on the screen. Thus I only look at LC when I am giving questions. IMHO it would be great if LC could deliver an audio signal when enough people say they are confused (customizable on number, of course). An electric shock would work better but a bit harder to implement.