Or "How to improve on a Gehry design." Somewhat off-topic, but I have a thing for these animated facade projections that have been appearing over the past couple of years. This recent one is particularly cool:
File under "If and when I get some extra time:" Use a Revit model to design and simulate a facade projection using the new Analysis Visualization Framework. Then hook the visualization up to a hardware system using openFrameworks and arduino to drive the projection. Or, one could project real-time data visualization about the building's energy and/or solar performance right on the facade - a public display of green-ness (or lack thereof.) One can dream.
Here are some more fantastic examples:
Architect Simone Giostra talks about GreenPix - a media art LED wall that is powered by the sun. Extra cool: they have built a free tool for simulating your own videos. The user interface is kind of clunky, but it demonstrates how one could start to simulate these types of installations using a 3D model.
UrbanScreen does some amazing work
Also from a couple of years ago, this is a bit more fanciful (made with After Effects not actual projection) but I love the decidedly low-tech approach