The recipe is at the end of the post, for anyone who wants it. Maybe two people here, but you never know. Some Flame...

The kids can eat it without harm, but most won't try it again. It's like taking a nice big swig of the Great Salt Lake. McCormick is manufacturing neon food coloring in addition to the regular colors now, so it's possible to get an enormous range of colors. I'll have to waste a bottle of coloring to determine how many drops are in 2 tsp, to use the formulas for blended colors on the backs of the boxes.

There's a non-cook recipe with oil and alum in it, which stains and leaves grease marks. Another has peanut butter as a principle ingredient, and is called edible, but I don't like to encourage children to eat anything that can be not-food. Apart from the peanut allergy problem in a public setting, too many things can happen later.

Telling children they can eat their art supplies is like taking small children mushrooming or berry-picking; until they're older, they can't be counted on to distinguish between edible and poisonous in the context of play. I know a family who lost a child a couple years older than me to medication overdose because she put a potent medicine in her dollies' tea. She drained their cups to pretend they drank their medicine, because that's what we do when we play tea party. One good reason not to curse child-proof caps.

A former nursery school teacher has told me there's a recipe using unsweetended Kool-Aid for color. That must be vibrant, and it would also have an attractive smell. The stuff I make has no fragrance at all.

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PLAYDOUGH: EDIBLE BUT NOT TASTY

Stir together in a saucepan:
**1 cup flour
**1/2 cup salt
**2 TBL cream of tartar (a powder, not the sauce, for the uninitiated)

Add:
**1 cup water
**2 tsp food coloring, any color. (Those little squeezy bottles of McCormick's that come in the box of four colors hold about 2 tsp each.)

Stir until mostly blended -- "some lumps" is fine -- then put the saucepan on medium heat and cook, stirring constantly, for 3 - 5 minutes, until it sticks mostly to itself but isn't entirely dried out. It looks like a glob and you may think it won't turn out, but it will. Let it cool slightly, knead in any remaining gooier bits and any remaining drier lumps, and put it in an airtight container or a plastic bag.
Adapted from Feed Me! I'm Yours by Vicki Lansky