This movie from BIG is a great example of how the ideas underlying a project might be communicated. Their work is quite analysis and diagram driven which helps them tackle very large sites and briefs albeit with often rather brash consequences. That said their thinking is very clear and has a direct relationship with their architectural organisation. By clearly, but succintly, explaining their thinking we understand the architectural proposals. I also find the combination of someone talking/using hand gestures juxtaposed with overlaid graphics, animation, stills and physical models very engaging and rich.