You have to find something to do between watching the bands, and you can't spend all of that time drinking and smoking because you'll eventually pass out and miss something really important. For the ever-resourceful hippies, the land they were on gave them the opportunity to build their own entertainment.
Surrounded by handy wood, thick branches and hay bales, it was easy for those with the ability to build climbing frames and play pens, which were as much fun for the adults as they were for the children, as seen here. We're not sure that modern health and safety executives would have signed off on this construction, but it looks solid enough, and diving headlong into a hay bale must have been fun. We're not so sure about the person stuck on top of that pole though, it looks a little uncomfortable to us!