Here is a great homemade playdough recipe that I have been using for years. It's a great activity for your pre-school age children to do while your schooling the older kids. I like the fact that it's safe if they happen to eat some. And it smells great!
1 cup flour
1/2 cup salt
1 pack koolaid (any color you like)
3 Tbsp oil
1 cup boiling water
Mix first three ingredients in a large bowl. Add the last 2. Stir until well blended. Remove from bowl and knead into soft dough. Store in air-tight containers.