Look At This blog has a mega-post about all things Halloween. A few fun facts from the site:
Black cats were originally believed to protect witches' powers from negative forces.
A pumpkin is really a squash, and comes from the same family as the cucumber.
About 99% of pumpkins sold are used as Jack O' Lanterns at Halloween.
The biggest pumpkin in the world tipped the scales at a whopping 1,446 pounds. This gigantic gourd was weighed in October 2004 at a pumpkin festival in Port Elgin, Ontario, Canada.
The record for the fastest pumpkin carver in the world is Jerry Ayers of Baltimore, Ohio. He carved a pumpkin in just 37 seconds!
The very first jack o' lantern was made out of hollowed out turnips.
http://www.npr.org/templates/story/story.php?storyId=95683613