If you are trying to grow a giant pumpkin, make sure to bury your pumpkin vines.  You can completely cover your vines so only your leaves are showing. If you keep the soil moist, a new root system will start growing everywhere the stems of leaves meet the main vine.  This will happen if you bury the vines completely.

Make sure you leave 3 to 4 feet of the vine on each side of the pumpkin unburied.  You can actually pull the pumpkin off of the vine if you bury too close to the stem.