I've seen it in Blender Nation:
http://www.blendernation.com/2013/03/02 ... ysics-demoAnd the best part of all this is that you can download the.blend file and try yourself playing around with it, as long as you have a appropriate graphics card and drivers. Open the .blend with blender. Then in "Game" menu and select "Star Game Engine". You can drag and drop objects with the left mouse button. In right side of blender you can see in the script all available actions. For example the key "B" throws balls and the "H" horses.

P.S.
If you experience difficulties when you start the game engine (small black rectangles in the image), press the number "0" key (from the alphanumeric keyboard and not from the number pad), to disable the filter GLSL.