Besides a good time to read scary stories, that is. (Stories like the ones found in All Things Dark and Dastardly, coming October 21st!)
I have a book called "Witches of the World" by Diane Canwell and Jonathan Sutherland that says Samhain, the precursor to Halloween and celebrated on October 31st, celebrated the end of summer. Samhain was a Celtic festival and the end of the year for them.
Many of our Halloween symbols and rituals derive from Samhain. Hollowed-out pumpkins, as well as other vegetables, were placed in the windows and on porches (the Celts evidently had porches) to welcome their dead ancestors and keep evil spirits away. One of these spirits, a very bad one, was called Jack-O-Lantern. This guy wasn't able to get into Heaven or Hell. That's a little inconsistent, since the Celts were pagans back then.
Irish and Scottish immigrants, this book says, brought us the custom of carving pumpkins. I'm glad. It's fun!
The Druids (which I think were Celtic priests, but I'm not sure) lit bonfires to guard against witches and spirits wandering around at harvest time. This book says that this was also the time when Druids imprisoned their victims in wicker cages, then sacrificed them on huge bonfires. Really? The poor little victims couldn't get out of a wicker cage? I wonder what sort of people were Druid victims.
Wiki says that Samhain in Ireland was the end of fighting and trading season, and was a time for tribes to get together. I'll buy that. Halloween today is the beginning of The Holidays. Time for stores to start putting out Christmas and holiday decorations and time for people to start deciding what they're going to do for Thanksgiving.