Has anyone else tried this? It's basically a space-agency simulator, where you run your own NASA, for the planet of Kerbal (which suspiciously has exactly the same gravity, etc as Earth). You can build and fly your own spacecraft, and put probes into orbit, or land on various planets and moons. So far I've managed to send an awful lot of astronauts flying out of the solar system in an attempt to make other planets, with success limited to a couple of satellites around the home planet, its nearest moon and the sun. Pretty nerdy, but still quite amusing.