Take a 2 liter soda bottle, poke holes in it. Attach to a garden hose. Toss over a tree branch and let hang for a kids water sprinkler. You can loop it over a tree branch and let kids bat it around for more watery fun!
If you have an inflatable pool, take it out and fill it with the comfiest blankets and pillows you own! It is the perfect activity for night time to look up at the stars. Great for date nights or just hanging with the kids.