It's summertime so let us talk about one of my FAVORITE games that is a quick set up and quick implementation. I call it flying saucers and it works cross age groups and can be adapted easily to give a challenge if needed.
2) Place the frisbee upside down on one hand
3) Keep your frisbee while trying to knock over everyone else's frisbees
4) Once out, they can do 10 jumping jacks and hop back in
END when they start to get tired!
But for real, super easy! You can easily adapt it to make it more challenging if you need. Instead of just running to knock over, you can make them crawl, jump, skip, hop, etc. Instead of flying saucers, you can change them to fit whatever your theme is too. Happy playing and good luck!