Major Nelson has posted a countdown timer for June 11, 2013, with the accompanying line "And it's on..."
Of course, June 11, 2013 is the first day of the E3 Expo, and it's a virtual certainty that this year's convention will unveil the highly anticipated next generation Microsoft console (codenamed Durango, and suspected of being officially called the Xbox Infinity.)
It's also possible that this upcoming E3 will also debut the Kinect 2.0.