Is This Window 8's New UI?

It appears Microsoft may have just leaked its own goods. Some sharp-eyed Windows fans spotted what could possibly be the next version of windows in a promotional video. A promotional video! Someone's getting fiiiii-iiiired.

what if this is the next Windows? We haven't learned much. The taskbar appears tweaked, but only very slightly. The Start Menu is square. There's a little clock in the middle of the bar. That, erm, seems to be pretty much it. Those looking for a quantum leap in Microsoft UI will be pouting. Those who subscribe to the If it ain't broke... school of thought will be content. Skip to 0:35 and see for yourself.

One more question, though: why is the little boy at the start of the video sloshing his cereal around like that? [WinRumors via TNW]