I've recently started a small addon project which allows to use the blender ui to control the gameengine. Possible applications are projectiions on multiple surfaces or videomapping. The addon uses osc to send the data of manipulated objects in blender to same scene loaded in the gameengine. It also adds the possiblity to start and stop media for bge videotextures from the NLA.
A short video demonstration can be found here:
the code is hostet on github:
If you want to try it, you need blender 2.63 and pyliblo. Be carefull the project is an very early stage. You also need to set the correct search paths for liblo in server.py and client.py. comments are welcome.