Given the type of people that frequent the boards here, I assume I can't be the only one here that can appreciate this.
NASA has a produced a Java based 3D solar system simulator that you can access via your browser at http://eyes.nasa.gov
The simulator will let you move back and forth through time and view the planets, planetoids, moons, comets and spacecraft (oh, and the sun) as they move through the solar system.
You can zoom in on the ISS and watch as it orbits earth or
Set the time to Aug 12, 10:00:00.0 PM (Pacific) and zoom in on the Mars Science Lab (MSL) and you can watch over the next 20 minutes as the MSL separates from its cruise stage, enters Mars atmosphere, maneuvers and deploys ballast, drops its chute, drops the heat shield, breaks away from the chute and makes powered flight to the surface of Mars before the Sky Crane launches itself away from Curiosity and crashes safely on the surface of Mars some distance away.
I have lost at least 2 hours, approaching 3, exploring the planets and spacecraft orbiting our sun. My apologies to anyone else who may be destined to lose time to this application as well.