The thing is, when you get there you are essentially living in a small prison cell.  At least until there is enough infrastructure to move around in.  But your activities are still limited to about what you can do sitting in a little room in front of a computer.<p>Just thinking about some small things, such as going swimming, or riding a bicycle on a path through the woods.  Or hiking &#x2F; camping, or driving a sports car along a twisty mountain road.