No one is very sure how far back the idea of carving pumpkins goes but the jack-o-lantern - you remember? Jack be nimble, Jack be quick, Jack jumps over the candle stick? - certainly has some American roots - there is a poem called "The Pumpkin" by Whittier in 1850:
Oh!—fruit loved of boyhood!—the old days recalling,
When wood-grapes were purpling and brown nuts were falling!
When wild, ugly faces we carved in its skin,
Glaring out through the dark with a candle within!
All of which (witch) is more than you want to know. Have a happy Halloween. Keep the cats indoors.