As I reported at Search Engine Land last night you can now make your mobile Google search results page into a bubble level (or spirit level). Just go to Google on your mobile device and search for either [bubble level] or [spirit level] and Google will return this interactive bubble that shows how much your mobile device is tilted one way or another.
Here is the animated GIF I made of it in action:
This was first spotted at reddit from what I can tell.
I'd call this a feature not an easter egg, as I said. I mean, it is more like a calculator then a goofy star wars hack.