http://kerbalspaceprogram.com/You can build your rocket and then launch your little buddies into space. I think you'll find that your favorite Kerbal will be Jebediah Kerman, the ThrillMaster.
The best part is that the creators used 3DMax to build the parts and they show had to do the programming for the rockets and other parts.
I currently have a mission running that is almost 24 hours in, over 206625 kilometers out and travelling at 2436 meters per second. Jeb is still thrilled but Bill and Bob are terrified.