This is a great recipe for homemade playclay. It's good for little hands as it is nice and soft and easy to manipulate.
1 cup water
1/2 cup salt
1 1/2 tsp cream of tartar
1/2 tsp food coloring
Mix the above over low heat. As it heats, add:
2 Tbsp vegetable oil
1 cup flour
Stir over low heat until the mixture starts to ball up, dry out, and pull away from the sides. When it's not sticky anymore, pour onto the counter and knead until smooth. (Careful, it's hot!) Keep in a sealable plastic bag or other container to keep it from drying out. No need to refrigerate.
*recipe adapted from First Art by MaryAnn F. Kohl