Microsoft's PlayXBLA site posted two "Secret Squirrel screenshots" depicting an unannounced Xbox Live game to be announced for real at E3. Of course, even without the title or any real details, we can get a pretty good idea of what the game's like: it's Avatar-shaped people racing and doing stunts on motorcycles in exotic, dirt-track environments.
With screenshots named "AMX_Mystery," the name "Avatar Motocross" seems like a safe guess. Regardless of the name, Xbox fans have proven definitively that they think bikes are neat – a trend that likely motivated the development of this mystery game.