I know there are a bunch of space nuts here in the group, so I'll post this here.
A classic game that I used to own on CD has been redone and made available for Windows, MAC OS and Linux- Buzz Aldrin's Race Into Space.
Its essentially two player Liftoff!
, which is known in my gaming group affectionately as "The Schadenfreude Game" or "Can't Stop With Rockets". Even my new Windows 8 machine, which is finickier than an 8 year old about broccoli, runs it like a champ.
You can check it out at http://www.raceintospace.org/
. From there, you can get the link to the SourceForge.org website with the appropriate download for your machine.
You can find the rules at "The Docking Module", an older fansite for the game which has the rules in a PDF. You can find them at http://peyre.x10.mx/BARIS/index.htm
Word of advice- DO NOT download the version of the game on the Docking Module. It's an older version and might not be stable with newer machines. I can vouchsafe that the SourceForge version is stable in both Windows and Mac, and hope to hear from a buddy of mine about the Linux version.
Liftoff is one my favority games of all time, and BARIS is a computer version that in some ways is better than the original board game.
Also, the game has a 'play by email' setting- I haven't tried it yet, but if anyone is interested, I'd certainly be up for a game by email.