Tomorrow is Hallowe’en.
It is an annual holiday celebrated on October 31 with origins in the Celtic festival of Samhain. It is also associated with the Christian festival of All Hallows’ or All Saints’ Day.
Samhain is pretty much a festival to celebrate the end of summer and also a festival of the dead. Ancient celts believed that during this time the passage between earth and the other world was very thin, and sometimes things could cross over. Good spirits were invited to hang out, and bad spirits were told to get lost. Also, since this was the end of the harvest season, it was time to get ready for winter.
Many Hallowe’en traditions come from the Samhain traditions, just like other “Christian” holidays. Dressing up in costumes, trick-or-treating, and carving Jack-o-Lanterns came from some Celtic tradition. In America we use pumpkins instead of the traditional turnips, because they were more readily available. The ancient Celts carved turnips to keep spirits away.
The name Hallowe’en comes from All Hallows’ Evening, which got shortened to All Hallows’ Even, which got even shorter to All Hallows’ Eve, and finally Hallowe’en (or Halloween).
Some Americans do not “celebrate” Hallowe’en because they feel the day is associated with devil worshipping or some other evil activity, and this is, of course, entirely untrue. The point of Hallowe’en was to keep the evil spirits away to make way for the more holy celebration of All Saints’ Day which is November 1. Other Americans do not celebrate Hallowe’en because of its Celtic, and therefore Pagan traditions, but hopefully these Americans also don’t celebrate Easter and Christmas, because both of those holidays are also very pagan in origin.
There are some religious people that don’t mind Hallowe’en, seeing it as a completely secular activity, and also for reasons mentioned above (All Saints’ Day). Some Wiccans dont’ celebrate the day, seeing it as a bastardisation of the true holiday of Samhain.
Popular media has inserted the use of devils, witches, and other horror movie type stuff because that sort of thing sells, and most of those have nothing to do with the original traditions of the day. The Jack-o-Lantern came from an old Irish story about a mean drunk who tried to trick the devil into climbing up a tree. Once the devil was in the tree, the man put a cross on the tree so he couldn’t come down. The devil then cursed the man to wander the earth carrying nothing but the light he had: a candle in a turnip.
You didn’t know before, but now you do.