Slip n slide-
A trampoline-
A skateboard-
Build a tree house with them .
Taking suggestions to keep two 10 year olds and a 6 year old entertained this summer. New crazy things they may have never done?
Beer pong
Tattoos
The art of spitting
Lawn Darts
Billiards
Swimming is always fun, no matter what :) Have they ever been on a roller coaster? :D