If you’ve ever wanted to know what it is like on the moon (or on a secret movie set, if you are one of "them" people) you can download NASA’s Moonbase Alpha for free on Steam. Anyone played this yet?
In Moonbase Alpha, you assume the exciting role of an astronaut working to further human expansion and research. Returning from a research expedition, you witness a meteorite impact that cripples the life support capability of the settlement. With precious minutes ticking away, you and your team must repair and replace equipment in order to restore the oxygen production to the settlement.Source: http://www.hardocp.com/news/2010/07/06/nasarsquos_free_game_now_on_steam/