Make a backyard bowling alley. Add food coloring to clear plastic bottles of water. Use party streamers as lane margins. Add glow sticks for night bowling. (These would make great outdoor table nightlights also with the glowsticks, gonna try it!
Shop for Run Mat at S&S Worldwide. Get their motors runnin' and movin' as a team! Get their motors runnin' and movin' as a team! Kids (or adults) walk along with the lead person pulling the mat down to keep it moving.
Bean Bag Toss Drill a couple of different sized plastic buckets to a board, and have fun seeing who can get the most bean bags in (or rings, rocks, balls, etc. Keep score by assigning the buckets with different points based on their size.