On Friday July,19 NASA's Cassini probe will turn its camera back towards the inner solar system. Since Saturn will be blocking out the sun it's a rare chance to see a glimpse of Earth from the outer solar system. From the JPL website:

We think Cassini's July image is a special opportunity for Earthlings to wave at our photographer in the Saturn system and learn more about my favorite planet, its rings and moons. We hope you'll go outside, look in the direction of Saturn and send us pictures of yourselves waving. You can share your pictures by joining our Flickr group Wave at Saturn, adding them to our Wave at Saturn Facebook event page or tagging pictures on Twitter #waveatsaturn. We hope to make a special collage of all these images if we get enough of them.

The Cassini portrait session of Earth will last about 15 minutes from 2:27 to 2:42 p.m. PDT (21:27 to 21:42 UTC).