We have a huge backyard here at the homestead, and we definitely put it to good use. My parents (who have an in-law apartment on one level) wanted to buy a big wooden swingset for the kids, but we vetoed that idea. Swingsets are okay, but they take up a ton of room and limit play. We prefer to keep the kids' play areas more natural and open-ended.
I'd been dying to find some sections of tree trunk somewhere, and was on the verge of calling a tree service to find out how much it would cost to purchase them. Then Doug and my dad took a few loads of yard debris to the city compost/dump area and found exactly what I was looking for. They lugged them home, and this is what I did with them:
I'd like to get some more to fill the gaps. Right now the kids climb all over them, jump from one to another, using the area as a stage for all their crazy pretend games. Two of the pots have pretty purple flowers (I forget what kind), and the other two pots have herbs.. thyme and mint. I'm very happy with the way it turned out, and the kids are, too.