This one is a toddler favorite.  This set of 5 pieces snap together with magnets in a three-dimensional-puzzle sort of way to create a concrete mixer.  The wheels really roll and the drum can rotate.  I have used this item in my class for an eye-hand coordination activity as well as a language activity; chassis, frame, grille, cab, and drum.

There are many different versions of this available.  Here are some.