Play-doh, play dough, modelling clay... whatever you want to call it. I'm not the crunchiest person around, don't weave my own yoghurt etc... though we sometimes do baking projects on the weekend (not completely inedible). This is a quick project (30mins tops) and the resulting Play Doh-like substance blows the real stuff out of the water. Seriously. Smoother, not crumbly atall and lasts forever (stuff pictured is at least a few weeks old). So, if fragrance free or gluten free or what have you are concerns you can now make your own organo-vegan-doh.
One tip though, if you use red food coloring, put a good amount in, or else you end up w/ pinky play dough that inevitably gets formed into *ahem* humourous shapes... Also, the pan that you cook the stuff in does get caked w/ the cooked dough, so that needs a good soak, only drawback.