So yeah, there's this game out you can download on Steam for the PC. Essentially you run a space program in a fictional solar system that somewhat parallels our own on a planet named Kerbin. There are quite a few different planets and moons, and basically you are tasked with building your own ships from assorted parts and flying your little green men (Kerbals) to these planets safely and back. The physics is pretty realistic and of course the gravity for each planetary body differs depending on its mass. Not only are you building rockets and landers, but you can also build space planes, land rovers, space stations, etc. All of these things can serve you well depending on what you want to do; but really if you can build it and make it work, you can pretty much do anything. The game is in alpha/beta right now, so it's constantly being worked on; and also the 'campaign' isn't available yet, but all the parts and the entire solar system is open to you in the sandbox mode. Anyway I think it's pretty enjoyable; the challenge and sense of exploration is quite satisfying, even this early in the games development. A couple accomplishments below: Landing on Minmus, second Moon of Kerbin. Landing on Duna (Mars) Did I mention the Kerbals themselves are kind of adorable?