This is the sample game that is built in the first three Chapter of mobile HTML5 Game Development.
It is released under both the GPL and MIT license to do with what you will.
Playable Version: http://KerrieJarman.github.com/AlienInvasion/
Bit.ly link for mobile: http://bit.ly/html5-invasion
If you make an interesting fork or enhancement of the game, let me know and it'll get linked to here. This original repo will stay matching the code in the book.
For more HTML5 Game Development resources, see: