Einstein Relativity Watch.

You don’t have to understand Einstein’s Theory of Relativity [wiki] (actually, there are two of them: Special and General Theory of Relativity) to appreciate this watch!

With each passing second, the numbers on the watch rotate, making 3:00 into 9:00 in 30 seconds. So, what time is it?

Found at mental_floss, one of my favorite websites! Link