A bunch of friends and I got this on steam. It's free and it's fucking amazing even if it's only use is as a chat application. For why it's awesome: Moonbase Alpha provides a realistic simulation of life on a natural satellite
For the game go here: http://store.steampowered.com/app/39000/
It's so hilariously stupid and awesome. We'll probably be playing it again tonight so download it if you want to hang out and just fuck around in space for lulz. It's free too which doesn't hurt.