"We're working on a project to bring you a new and improved Google experience, and over the next few months, you'll continue to see more updates to our look and feel. The way people use and experience the web is evolving, and our goal is to give you a more seamless and consistent online experience—one that works no matter which Google product you're using or what device you're using it on," explained Google last month.
After launching a new interface for Google Search, Google created two themes that preview Gmail's new design and started to test Google Calendar's new UI and Blogger's new UI. Up next: Google Docs, Google Sites, Picasa Web Albums, Google Reader and probably other services.
{ Thanks, Kon. }