Been playing it for a week or two now and just now I managed to successfully dock two hand-built vessels in LKO (low Kerbin orbit).
To those unfamiliar with KSP, this may sound like a trivial accomplishment. But no. To do such a thing requires a lot of thought and sadly a lot of stout and
I now have a fully functional (and extensible) space station in orbit and thus a platform to refuel and launch future long-distance missions from.
Here's a couple of screenshots from my mission...
Before docking (the main space-station vessel is on the left, the other ship is the "shunting wagon" which will perform refuelling duties)..
And a NASA press-corps image from after the docking process (which was fraught with stress and much fine-pitch thruster action)...
If you are a science nut like I am and love to learn about orbital mechanics, you should have a go at KSP.
Oh, and forget about going outside ever again if you do. :)