Rumor has it that this footage, which leaked yesterday, is from a video that Forza Motorsport developers Turn 10 are set to unveil at E3 in June announcing Forza 4. That Turn 10 has been developing the game is no secret, and the Kinect functionality is something that we actually saw first-hand at last year's E3, so this smells legit to us. Until there's official word from Microsoft and Turn 10, however, it's all just speculation.