Paint a fresco (FuoriBorgo)
Make your own bug catcher (Shivaya Naturals)
Craft up some clay suns (Twig and Toadstool)
Make some Custom Drawn kid stationary (Just Something I Made)
Have your kids make their own ink Blob t-shirts (Vintage Chica)
Make mobiles from found drift wood and beads (Wise Craft)
Try some corn syrup painting (The Crafty Crow)
Make a moss terrarium (Poppytalk)
Learn block printing: tutorials Part I & Part II ( from me!)
fold up some Origami paper wallets (Future Craft Collective)
Squeeze some fresh orange juice and make sun eggs (GardenMama)
And more lists to pour over!
The Long Thread's round up of 50 Summer Crafts for Kids (check out the Stone Dolls from MayaMade)
list of great games to play with kids over at Mommy Coddle
List of outdoor summer activities at 5 Orange potatoes
list of Artful Books for Children from Quince and Quire
and this list of resources for nature-based summer learning, from The Snail's Trail