Yesterday, NASA announced that it (along with international partners) had discovered seven Earth-size planets orbiting a single star. Even more importantly, three of them are located in the star's habitable zone, the range around a star where liquid water is possible. The solar system (named TRAPPIST-1) is unfortunately located 40 light-years away from Earth, so sending a probe or a person there isn't really possible for now.
Still, it's a very important discovery, and Google is commemorating the event with a Google Doodle. If you don't feel like going to the Google homepage, here's the full animation:
The doodle should be visible for everyone, both on the Google homepage and the Google Now app on Android.