1 box cornstarch
Water
Food coloring

Mix water into cornstarch until it looks like "Elmers Glue". Add food coloring. Play with fingers - it will be hard while moving and liquid when movement is stopped. Cleans up very easily with water. When dries up, just keep adding water. Non-toxic (OK for toddlers). School-aged kids love this!! Great in bathtub (turns into water - softened).