Giant Connect Four! Take a shower curtain, spray paint it yellow and leave "holes" for the game pieces. Grab some plastic plates from the dollar tree and throw on Velcro on the back of the plates and where the holes are, then use Velcro to hang it from the wall each time you want to play.
DIY American Ninja Warrior Backyard Obstacle Course
could do bug obstacle course DIY American Ninja Warrior Backyard Obstacle Course - Five different elements. Build and re-build this obstacle course, and then it breaks down for storage. Storage ideas in the post.