Today's Google Doodle is a gently animated Calder mobile in honor of the artist (who would have been 113 today if he were, say, a tree, or giant tortoise, or something else that actually lives that long), and is charming in its subtle movements.
It comes to rest shortly after the page loads, but if you click on it, you can set different parts of it into motion, and they will drift for quite some time. It's nicely done.