My kids love to play outside. But, even more so since we've put a couple of swings up. Kids naturally want something to climb up and over and explore when they're outside. Providing safe areas to do that is our responsibility. You can either buy or make a play area. We have both. My kids got a small play structure - the "fort" - a couple years ago. It's got a slide and a climbing part. But, they seem to like the stuff we've made or the natural objects even more.
We put up a traditional swing and a twirly swing a couple of weeks ago. They love the traditional swing, but they may still be a little small for the twirly swing. Here they are sharing a ride while I try to get a picture of them together.
A couple months ago, we also cut down a pine tree that could have the potential of falling on our house. The tree was about 60 feet tall and we now have big 6 foot sections around the yard. My kids love these. It's like climbing a tree - only horizontally instead of vertically. It makes me nervous, but I know other than some probable scraped knees, they're pretty safe. Eventually, I want to roll these sections into a circle around the fort and swing area to kind of contain the play area.