Buy dumbbells/kettlebels and swing them around like crazy? Fill up a big bag with sand and try to throw it over your shoulder 10 times, then sprint to it and carry it back on your back (even if it doesn't end up far away from you)?
Are there mountains near? I'm not suggesting you start mountain climbing without any proper training or equipment, but maybe you can stay at the foot and just climb some big rocks?
I must note that I'm not fully Primal (well, if you consider potatoes and rice Primal, then I guess I am Primal) and I don't do any of the above. I would if I had the space for it. I certainly have the time. But that are just a few things that you can do in relatively short time (10-15 minutes) and don't require a gym membership (or friends. ).
It depends on what you think is fun, though. You might see that as "workouts" instead of play.