If you need something educative for your children, Stellarium makes the introduction to the mysterious world of astronomy. Stellarium is not just a game, it's a useful tool for anyone into astronomy.
With Stellarium you will see amazing 3D photo-realistic skies rendered in real time. It displays stars, constellations, planets, nebulas and others things like ground, landscape, atmosphere, etc.
Stellarium works on OpenGl, is small, less than 50 Mb and is available for both Windows and Mac.
