As I was reading Digg this morning, a lot of folks had dug an article about remembering the taste of Play-Doh. The things people reminisce about! However, it reminded me of the many times in my childhood when we were snowed in, and mom made homemade playdough, and it was perfectly safe to eat, although I recall it was very salty.
One of the commenters mentioned edible playdough as well, and provided a link to a page all about, yes, edible playdough. There are more links below to other recipes. There are two types, ones made with peanut butter, and ones made with flour. A properly stocked prepper's pantry should have all the ingredients needed to keep small children entertained fairly quietly.
I recall that mom actually had a book with the recipe, and other fun, quiet activities. That book is probably no longer in print, but if you have children, a similar book would probably be a good idea: