Here it is, straight from the guy who made it.

1 bowling ball sized sugar pumpkin
2 pounds of ground beef
1 to 2 medium sweet onions (vadalia)
1 to 2 green peppers
2 cups of rice
salt and pepper to taste (and remember the pumpkin doesn't
        have any salt in it)
1/2 to 3/4 pounds of ground pepperoni

brown the meat in a skillet
cook the rice
dice the onions and peppers
put that in the ground meat
salt and pepper it
throw in the pepperoni
mix it all up
get a big bowl
put the cooked rice and mix it all together
hollow out the pumpkin
stuff the pumpkin
put the lid back on
turn the oven to 325 - 350 degrees F
put the pumpkin in a pan
fill the pan with 1 inch of water
"tent" the pumpkin with foil
bake for 2 to 3 hours, till it turns dark burnt orange
optionally let it sit in the oven overnight for a marianted effect