I found this nice video that compiles a whole bunch of Sketchy Physics SketchUp models. All of the models can be found in the 3D Warehouse (so I understand), and the video shows snippets of how each model moves, interacts, etc.
Here's another one:
There is almost no documentation on how to use Sketchy Physics - a few very smart people figured it out on their own and are using it brilliantly. I'm hoping I can produce a Sketchy Physics book that makes this accessible to everyone.
Anyone can design anything in 3D! http://www.3dvinci.net/