I'd like to add two great pieces of software for astronomy nerds, Stellarium and Celestia.
For those who don't know and might be interested,
Stellarium works as an hour-based, location-based observable star chart with ephemeris for lots of natural and artificial objects. It can also predict Iridium flashes which is kinda cool !
Celestia is a 3D simulator of the universe. I love browsing the object library and from there see how constellations are twisted depending on the star you're getting close to. One passage in the last book of the Foundation series got me hooked to this little game
There are also trajectories for Cassini & Huygens (depending on the date you select you can witness how the probes entered Titan and Saturn atmosphere...), MIR, the ISS, and there's also a huge collection of custom objects made by the community you can add. Want to add the USS Defiant orbiting the moon ? No problem