Having heard some good things recently about HTML5 and it's current level of support amongst the various browsers, I decided to dig in and check things out.
On a recommendation, my first stop was to check out Dive Into HTML5  and HTML5 Rocks . Both of these sites proved to be excellent ways to get acclimated to the new features of HTML5. Dive Into HTML5 is more of a introduction guide while HTML5 Rocks is more of a interactive playground. Both were very helpful in getting a good idea as to what HTML5 can do.
Here is a link to the game: www.mikusa.com/snake/snake.html
In addition, I've released the source code under the GPLV2 license. Here is the link for the source code: snake.tar.gz
While this simple game doesn't get into all of the new features of HTML5 (just uses Canvas & Local Storage), it did give me a good introduction and get me excited to try out more of the new features.
 - http://diveintohtml5.org/
 - http://www.html5rocks.com/
 - https://secure.wikimedia.org/wikipedia/en/wiki/Snake_%28video_game%29