Playdough is just wonderful stuff. It's great for smooshing and mooshing (which means that it helps develop fine motor skills). Little people (and big people) can create entire towns of trees and buildings and dinosaurs which makes for great role play.
Here's a microwave recipe for making playdough which is very easy. You can add a few drops of vanilla essence as a perservative, but it's got so much salt that it will last for a while. It will probably dry out before it goes mouldy. There's no nasties in it so it's ok if some ends up in little mouths as well.
2 cups flour (plain)
1 tbspn oil
2 cups water
1 cup salt
1 tspn creat of tartar
Few drops food colouring
Mix all ingredients well. (You can leave the food colouring out if you want to add it later to make swirls. You can also split the mixture and make different colours if you wish.) Microwave on medium/ high for 2 - 3 minutes. Stir. Return to microwave for 2 more minutes.
Store in an airtight container and enjoy!