Digg this up and give the author some love: http://digg.com/pc_games/Fantastic_Universe_Simulator (and by the way, there’s a video linked from the Digg article, so check that out too).
It’s a pretty amazing project… everything is controllable via a WiiMote. I’ve seen this running on a huge projection screen, and it’s frankly just dazzling. You could play with this for hours.
Especially the galaxies crashing bits…
Here’s a screenshot of a physically accurate Saturn, with all of its moons: