You know what that is -- it's when you use a game engine to create your own animation. It's supposed to be a lot faster and easier than traditional 3D animation rendering methods.
www.machinima.com/
en.wikipedia.org/wiki/Machinima
www.machinima.org/
And an added advantage could be that you could also further use it for developing a game, or at least demo'ing a concept for a game.
I dunno if you've been to www.gametrailers.com recently, but game engine rendered cutscenes for the newest generation of games is pretty amazing in quality.








