I found this fascinating quote today:
When I was a kid, we played outside with the other kids in the neighborhood with most of our free time. We also made the most of recess at school. We kept ourselves quite occupied without any of today’s modern technologies. Listed below are some no-tech games that you may have enjoyed as a kid. I sure did. Some can be done indoors. Some can be done by yourself or with just one friend. But most of them are best when done outside with a group of people. Also, most of these games can be changed or improved by making up your own rules. Use your imagination!wired.com, 30 Classic Games for Simple Outdoor Play, Aug 2009
You should read the whole article.