EUGENE, Ore. -- The children race to the sand, squealing. Their teacher calls for them to finish lunch -- to no effect. "Today I'm finding the dinosaur," declares a barefoot boy, pants soaked to his knees. He dams a small stream running through the pit and surveys his domain: an expanse designed to look like a paleontological dig. Then he burrows into sand he believes conceals the life-size metal replica of an ichthyosaur, a Jurassic Age reptile.

The sand pit full of squirming 7-year-olds is just one of the many draws of a new kind of playground called RiverPlay Discovery Village, which opened last year.