I had a moment of confusion when I thought that letting my kids scoop cornmeal indoors was a good idea. It did keep them quite busy for awhile, however, they didn't seem to grasp the concept that the cornmeal needed to stay in the blue table.
I wanted to fill the table with different substances each week, but the constant sweeping of cornmeal kind of turned me off. Oren took it upon himself to fill the table (and my bookshelf) with flour and then dump water all over it. Water and flour make glue. That was fun to clean up.