I thought the mormon special was very interesting. You could tell the difference between the historians that were documenting the history with a view to preserving it, and the "historians" who had the light of fanaticism in their eyes who were "documenting history" with a view to spinning it to their favor. I found it amusing how Woodruff's compromise/directive on plural marriage, was in later years turned into "revelation" by the church leaders, and for the most part it was unquestioned by the rank and file, even though it clearly was a direct contradiction of the "revelation" to Joseph Smith about plural marriage.
I also found it fascinating that the change was due to financial and political pressure, which reminded me of various changes, most significantly the donation arrangement, made by Watchtower. I wonder if the "alternative service" changes fall under the same heading. Interestingly, as I was watching, it struck me that the JWs use of "new light" is simply a very subtle way of saying "revelation," and the two are really not that different, despite all the derision we (as JWs) pointed toward the LDS for their believe in personal revelation.
I still haven't finished watching it, missed about 90 minutes all together and will be watching it online later.
For people interested in seeing "Knocking," once it airs on a PBS station, it likely will be available online for up to a week afterwards.