Same idea, thought further:
http://www.kamibox.de/de_bonobox

You can make your own mini 3D projection.
Visit www.kamibox.de to download the template and the projection image.
Written instructions on www.instructables.com
How does it work? The iPhone mirrors its screen in the foil, but only the parts that are not black. These seem to be floating in space and are mapped on the car.

Music: Decktonic Fair Game