What is the new Google bubbles homepage all about?

Have you seen Google recently? They're up to old tricks, putting up a new UK and US homepage which will cause a storm! A little more simple than the previous 'Pacman' inspired homepages, but it's simple look and flying bubbles that react to the mouse cursor are great fun!

So what's it all about?

Some new way of using HTML5? perhaps? Just a bit of fun? Maybe?! Who knows, if anyone knows let me know and post up a comment.