Mental Canvas will unleash some serious creativity!
Also see:
Mental Canvas: App for drawing in 3D — from microsoft.com in Germany; Google translated the excerpt below:
When I first saw Mental Canvas in action, I was instantly impressed. Drawings are created in 3D in the app. You can even fly through your own sketches and comics. Mental Canvas offers teachers completely new possibilities to design blackboard pictures, to illustrate content and to try out creative things. The tutorials and examples immediately make you want to draw in three dimensions. Mental Canvas is currently available as a free download. In this blog article you will get to know the app.