love the countdown on the actual website http://www.google.com/events/io/2011/. No one likes looking at a boring old countdown timer
So, it looks to be built on the Box2DJS Javascript physics engine: http://box2d-js.sourceforge.net/
The author, Matt King, says he recently got into Javascript through Crockford's "JavaScript: The Good Parts," and seems to be knocking it out of the park: http://mking.me/