In a large pan with sides or on a tray with sides, pour in a bunch of cornstarch. Add a little bit of water. Let the kids mix it up with their fingers. If it's too stiff to mix, add more water until it's just a little bit stiff. Add toys like funnels, measuring cups, wooden spoons, spatulas, or be creative! To save this mixture, let it dry out completely, then put it in a plastic bag for another rainy day.

From Jane Billman