Instead of throwing your pumpkin away, fill it with bird seed and let it serve as a feeder for birds. When it starts to get soft then compost it or refill with seeds and throw it into the woods.
I normally just paint ours for Halloween, so I can cook it later. Link -via Buzzfeed
http://www.zogdo.com/ideas/carved-watermelon-skull-brain/
It's kinda sad how many people don't just compost their pumpkins in the back yard (people who ahve back yards, of course). I like to get old jack-o-lanterns for my box, and for my back garden. I'm trying to improve the soil.