Polygon has a very nice long form article up about Kerbal Space Program, my favorite video game, how it came to be, and the fact that it will be collaborating with NASA! Well worth a read.
“Kerbal Space Program is, at its core, a rocketry simulation. When it first became available for download it had a limited scope. There was a large hangar full of parts and little green pilots, a launchpad with a button to push and a patch of sky to fall through when it inevitably all went wrong.
Since the day it was released, less than three years ago, KSP has grown to be so much more. Beneath its childish surface lies a complex physics system churning through mathematical calculations so expertly, real rocket scientists would blush to see it. KSP has even earned the respect of NASA — many of its employees play it regularly.
These past few months the team at KSP and the team at NASA have developed a professional, although distant, relationship. And this year they will begin to work together.”