Over at Geek Dad, Jonathan Liu has suggested The 5 Best Toys of All Time, which include a stick, a box, string, a cardboard tube and dirt. Be sure to read his reasoning.
I'm very tempted to give these - each individually wrapped - to my nephew for Christmas this year (in addition to a few toys and other goodies). He's only five years old and so at the nearly perfect age to enjoy them. He wouldn't likely understand the humor, though his parents probably would,