I just watched almost 1h30 of one of the most interesting presentations I've ever seen. It is about Microsoft Office 2007 user interface. And it is not because it is about Microsoft or Office, but it is very interesting to see how an innovative process can happen within a company. I've always been curious about what had driven this UI decision change and how process took place.
You can watch this presentation here. There is even an iPod version that you can watch on the go.