Space engine. A space simulator that is really, really good

[Ignuus66]

Explanation: Space engine is a highly realistic simulator that procedurally generates the entire universe down to every planet, It is difficult to describe so I will let a video do it.
http://www.youtube.com/watch?feature=player_detailpage&v=6Y61_cVfDiI
here is a guy showing planets with life he randomly found:
http://www.youtube.com/watch?feature=player_detailpage&v=FmvyF6bx7SU

Every dot you see in the video is either a star you can go to with planets moons and asteroids around it, or perhaps a galaxy with million or billion of stars you can visit, and there are billions, possibly trillions of galaxies generated.
Also, it is completely free and you can download it here:
http://en.spaceengine.org/

It does need a decent computer to run it, and it may crash a lot due to being in alpha stage, but it is well worth it.