Cuboro is one of our favorites here at Oh! Toys.  Part marble run, part puzzle and part developmental and educational marvel, Cuboro is truly a "heritage toy" -- one which not only can be passed from one generation to the next, but which children will come back to time and again as they grow and become more sophisticated about their creations.    While Cuboro needs no instruction manual, the Cuboro Book is an excellent guide for those who want to approach their constructions with a more structured approach.  Basic techniques are illustrated with photography and clear diagrams and will enable the reader to build a number of sophisticated marble runs.  Ages 3 and up.