Wash each pumpkin. Cut top 1/4 off each pumpkin; remove and discard seeds and fibers. Cut the tops of the pumpkins into small cubes, trimming off and discarding the pumpkin skin from each cube. Mince the pumpkin cubes in a food processor until pumpkin meat is finely ground.
Preheat oven to 350 degrees.
In large skillet, saute meat until no pink remains. Add onion and celery and cook 5 minutes longer. Stir in minced pumpkin, rice, tomatoes, eggs, salt, basil and thyme.
Place pumpkins in roasting pan. Pack stuffing into pumpkins. Extra stuffing that overflows can be placed at the base of the pumpkins, in the pan.
Place a piece of aluminum foil over top and crimp it over the sides of the pan.
Bake 45 minutes or until pumpkins are just tender. Watch carefully at end of roasting time so pumpkins don't overcook.