http://cgcookie.com/blender/2010/05/20/game-engine-part-2/
In this Blender Video Game Engine Tutorial, I cover setting up gravity dynamics, boxes that can be pushed around with Eddie, a « pushing » pose that Eddie goes into while doing the pushing (a « near » sensor). We also go into multiple scenes, and going back and forth between them, as well as a scene reset, in case you fall into the oblivion.
Source