Kids love an art project that ends up being something they can play with. This long reach "gizmo" by Teri of Giddy Giddy is a perfect example.
The main materials you'll need to recreate this gizmo are cardboard and Brads (the fasteners). It's a great lesson in leverage for preschoolers. For super-detailed instructions and more photos, check out Giddy Giddy.
(Image: Giddy Giddy)