Google gets ballsey on the UK homepage

It's Sept 7th 2010 which must be special (for Google anyway) as their UK homepage now has a set of balls (or are they balloons) that swirl around as the mouse goes near them and then they settle back into the semblance of the Google logo.

Google usually modify their homepage on specific anniversaries and it could be the date Google opened their doors in Menlo Park on Sept 7th 1998, which they have celebrated previously so it would make it the 12th anniversary, but why bouncing balls which look more particle physics?

Chris Heilmann who's Yahoo's Developer Network evangelist has published the source code (reverse engineered) to how they've done it based on HTML/Javascript and CSS.

Google do publish a list of their logos but today isn't on there yet.