Great list for Outdoor Summer Fun. Some new and amazing ideas I haven't seen yet to keep kids busy this summer. Worth a look for the links alone! 30 out of the box ideas (and awesome links to support you in doing them.
35 amazing things to do with crayons. Pictured is Melted crayon Pointillism.
For kids: Salt painting - Cardstock or heavy paper, white glue, food dye or water colors, salt, paint brush. Draw with white glue, cover with salt, dump excess, wet paint brush with color, touch to glue - watch color spread!
This set of 10 rainy day activities for kids is more active than many of the lists here. Some old stand-bys, a couple of messes, but also some really creative ideas to keep boredom from winning the day!
Food Painting ~ Have kids who love to paint and eat snacks? Then they will love this fun indoor activity! Grab some marshmallows or popcorn, then make edible paint by mixing milk and food coloring together. For a thicker paint, try sweet evaporated milk.