NASA scientists are having a lot of fun with Messenger, the spacecraft now orbiting Mercury. Not only they are documenting the planet at a resolution of 200 metres per pixel, but they are spotting all kinds of fun stuff. A few weeks ago it was the Sesame Street's cookie monster. Today it's a smiley crater.
It looks like even the craters on Mercury have heard of Bob Ross! The central peaks of this complex crater have formed in such a way that it resembles a smiling face. This image is oriented so north is toward the bottom.
So far, Messenger has taken 88,746 images "and extensive other data sets." After completing its primary mission—and still working like a champ—the spacecraft is going to capture another 80,000 images. [NASA Goddard]