Fun outdoor game for kids and adults. Use frisbees and paint the back side of them. How to make a unique bean bag toss game from terra cotta pot saucers and a printable (which you can get for free by clicking through!
DIY Sand and Rock Box by FSPDT. Gdjk -> made this with toilet rolls (aka tunnels) and moon sand instead of play sand. My son loved playing with it. The moon sand cleans up nicely indoors but play sand will be easier to play with when using the small cars.