de_Monteynard: I've been a fan for over a year and a half now and since the latest version 0.18 includes docking, it's time to spend a bit more time on it. However, if you have an addictive personality, stay clear of KSP! You'll be "testing one more rocket" and the next thing you know, you've spent your entire day trying to set up your Mun base.
Okay, it does sound like they've added a lot more features since I tried it. Back then, you could fly up... and then you could fly back down again, and that was pretty much it.