i laid down a flattened cardboard box. I sat my son (3.5) down next to it. Turned cartoons off.
I filled two pots; one with dried egg noodles, and one with dried beans. Produced a few plastic cups, lids, a set of toy wheels, and some utencils.
Hours of not too messy fun.
This is awesome!
Lay down an old sheet next time - even easier clean-up since you can just pick up the corners and everything slides to the middle. Rice is fun to play with as well, and even smells good.