I got a new video card in anticipation of playing SimCity 5 (which I luckily was able to get a refund for, what a piece of crap) but it motivated me to purchase another PC game I had been hearing things about. I can't recommend Kerbal Space Program enough. Its still in development, so right now its just a sandbox game, but its so much fun and very challenging. The idea is basically you build space ships, launch them, the pilot them. The characters are cartoonish, but the rockets, physics, and solar system you play in are very real. There is no official goal or career path yet, but thats fine with me. Right now just getting a craft into orbit is challenging. I finally got a space station started, and I've also been able to do a flyby of the moon. Actually landing on the moon and docking with the space station are the next steps. I may integrate them, upgrading the space station to be a refueling station. You can also build space planes which I haven't even touched yet.