Learn something about HTML5 via the simplest game

I was thinking, I should learn about HTML5.

I thought, maybe I should look at making a simple game in HTML5 

What's the simplest game? Pong.

So I googled 'pong in html5' and got this:

http://cssdeck.com/labs/ping-pong-game-tutorial-with-html5-canvas-and-sounds

It has a multi-pane window approach and you can see the code results on the right, instantly.