Wet noodle is so fun. Watch this demo! Tape a cup full of water to the top of a pool noodle. I'd tape a "hold here" on the noodle. The kids race to pass it up and down the line without spilling the water.
Angry Bird Game. Interesting things to do out there in your backyard. So simple and cheap to make, and you could play them with your kids or family anytime. http://hative.com/creative-and-fun-backyard-ideas/