I usually give kids in the 4th and 5th grade a choice in what they want to make out of clay. We start with a one day workshop where I go over the basics of working with clay and the clay tools. After that, the kids create either pinch pot creatures or creations of their own, I'm always amazed that a few kids come up with their own ideas and take the project to another level.
I just posted a bunch of pictures here.
Here are a few samples: