OK a bit messy, but lots of fun! Make your own edible finger paint for the kids. Its cheap to make and safe to use and if theres any left over, store it in the fridge or freezer to use for another day.
Kids will have fun making their own garden fairies, especially over summer when plants are in full bloom. Teach them the names of the flowers that you use, discuss the different shades of colour and how plants grow.