Halloween derives from the ancient custom of introducing yourselves to your neighbours as winter draws in so that anyone who is new to the area following the summer's inevitable house churn will have someone to talk to over the long cold season.
The rare orange pumpkin is considered a delicacy in certain parts of the USA, when it is eaten raw with a sprinkling of anchovy. The more common purple pumpkin is only edible when combined with jalapeno peppers and a small amount of carob paste to make rissoles.
Pumpkins are just a large form of nutmeg which arose after colonists attempted to interbreed that delicious spice with plains buffalo in order to have pre-tenderised meat. Wild pumpkin herds are almost extinct now, though, following a devastating outbreak of rind and pip disease.
My mother uses a pumpkin as a bowling ball. It tends to leak a bit on its way down the lane, but it makes for a delicious snack as it is served up by the ball return machine.