Marble Races with a cheap pool noodle (occupies the kids for hours.) Did this, but instead of cutting the pool noodle, the marble is small enough to fit inside the full noodle to roll down. Then can use the noodle for other things too!
24 Fun Outdoor DIY Projects That Will Keep Your Kids Entertained This Summer
Bubble mix doesn't last long in the hands of a child. Create a bubble station to provide a solution. This is so clever! / Only clever until the solution falls below the top of the bubble wand loop - then it doesn't work.