Found it:

http://i.imgur.com/eXGWz.jpg

Edit: This looks ominous:

    .fooled-image{position:absolute;top:55px;right:-30px;width:160px;height:243px;background:url(/static/img/you_have_been_fooled.png) no-repeat;}

Where is that quoted css ("fooled...") from?

The current css which is up on the fiber.google.com site:

    http://fiber.google.com/static/css/rel/portal.css?v=18c3b45c08597bad573f68d9f62a28cb

Maybe it has to do with their previous April Fool's joke? (you can see it on the Google Fiber blog)