This is a great clay recipe if you have kids.
3 cups flour
1 cup water
1 cup salt
1/3 cup oil
(You can add food coloring if you want to)
It stays soft in the refrigerator, although I'm not sure how many days it will stay soft. You can't leave it out too long because it hardens.
If you want it to harden so you can make beads and your little girls can make necklaces:
Form beads from the clay. Run a toothpick through them. Dry on a cookie sheet in a 225-degree oven for about 15 minutes on each side.