Gizmodo also has a link to a scholarly article on how ancient people "saved" the pumpkin.
The earliest variations were domesticated in Mexico, and bitter, but they ate the seeds and later manipulated the plants to be less bitter.
But what about North America? archeologist have found gourds (from Africa?) and squash (independently domesticated or from Africa) were used by the early Amerindians in North America...the gourds were important for storage in the days before pottery was developed.
more on the Eastern agricultural complex HERE.
lecture course link