Here is a field-tested ooblick recipe contributed by GLS:
1 cup cornstarch 1 cup baking soda 3/4 cup water N drops of food coloring
This recipe isn't quite as non-Newtonian as a pure cornstarch ooblick, but has an appropriately slimy feel.
Some, however, insist that the notion of an ooblick *recipe* is far too mechanical, and that it is best to add the water in small increments so that the various mixed states the cornstarch goes through as it *becomes* ooblick can be grokked in fullness by many hands. For optional ingredients of this experience, see the "Ceremonial Chemicals" section of Appendix B.