Children love something that is all their own. You can give them a patch in the garden and let them decide what they would like to grow. Flowers, vegetables. Preferrably something that doesn't take too long to grow to begin with.
Mud, water, plates, spoons and a wild imagination and you have the perfect setting for serving the family any creation made.
Isn't it amazing how the simple things are making a come back in what we should be doing and encouraging our children with. The world is their oyster, let them roam and imagine.