I'm sure you've all heard that the original jack-o-lanterns were not made of pumpkins. (I'm too lazy to look up a citation for that, so just go with it).
Anyway, today I carved faces into things that were not pumpkins. Specifically, a potato and an apple. To my surprise, the potato worked better than the apple - the apple fractured during the coring process and I was forced to eat part of it.