Lesson study
During my student teaching, I had the opportunity to do this--and it did not turn out great. The lesson was not authentic, as students were too busy wondering why there were other people in the room. I'm not sure if it was just the way we were required to structure it, but it just kind of seemed like one of those things that worked in theory, but not in practice. However, I would love to have another shot at it, now having the experience of the previous lesson study. It seems like a really great practice, so I would be interested in trying it again.