This is what you need...
1 1/2 cups hot water
2 cups Elmer's glue
Food Coloring (use as much food coloring as possible to really come out in the gak)
Mix all of these together completely.
4 tsp Borax
1 1/3 cups warm water
Mix together until completely dissolved.
Pour bowl 1 into bowl 2, but don't mix.
Lift Gak out and knead into shape.
**you can find borax in the detergent aisle at the grocery store, normally under name Mule 20.
Safety of Borax
The following recipes contain Borax, which is a toxic substance. The experiments should not be done in the kitchen nor near food or food preparation areas. Limit the time children are exposed to it, and tell them never to put it near their mouths, nor eat until their hands are washed. If they have an upset stomach or rash afterwards, push fluids, and the symptoms should go away. When interest has waned, use to kill ants somewhere away from children and pets.
**We used about 15 drops of blue and it only came out as a pale blue, so seriously you need to add tons of food coloring.
**Also, we added food coloring to bowl 2, but I think it's better to add it to bowl 1, which would probably bring out more of the color and give you a base for whether you should add more or not.