NOTE: This was originally posted on November 30, 2012. For information about the current version and price of Kerbal Space Program, see the KSP website. The rest of the posts in this series were made over the months as I learned to play KSP.
I ran across a great new game: Kerbal Space Program. It's a game where you run the space program to launch Kerbals (the inhabitants of the planet Kerbin) into space. The program is still in Alpha versions available for Windows and Macintosh. Version 0.13 is free, but the current version (0.17) is $18 (which also entitles you to all future updates).
You assemble rockets by dragging together parts in the Vehicle Assembly Building, panning around the rocket as needed to make sure everything is in place. Then it's out to the launch pad to learn to fly. The Kerbal astronauts onboard don't pilot the rocket...you have to do that with the controls and celestial navigating Map mode... but you do get to watch their changing expressions as the mission goes along. I crashed many a rocket spectacularly in the demo game before getting the hang of certain things about building and flying the rockets. The physics engine is good, and you need to have some understanding of orbital mechanics to get where you want to go. Once you learn to get into orbit, you can then try to land on the Mun or tiny Minmus (satellites of Kerbin), or (in the newest versions) travel to other planets and their moons (which I have not attempted yet). There is also a hanger where you can build jets or rocket powered aircraft, which I have not tried yet either.
Here's the Big Buté rocket that I used to for my mission to land on the Mun lifting off from KSC (Kerbal Space Center).
Here is the spacecraft in munar orbit. The two side fuel tanks are nearly empty at this point and will be jettisoned after I use the rest of the fuel in them to start my descent.
Astronaut Gusden Kermen during his EVA on the surface of the Mun.
I noticed a strange feature on the horizon, so I guided Gusden to it with his rocket pack. It was quite a ways off, and it took most of the rocket pack's fuel to get there and back again. I thought at first it might be some alien artifact (it kind of looked like a Star Gate on the horizon), but it turned out to be a big stone arch.
And I returned Gusten safely to Kerbin.
It was the day after I first posted this that KSP 0.18 came out (price $23).