Next to Christmas, Halloween is the most commercialized celebration in the United States and Canada. This ancient festival originated far from North America however, and centuries before the first European set foot on the continent.
The ancient Druids 督伊德教(古代高卢人与不列颠人的一种宗教)的教徒 who inhabited what we now call Great Britain placed great importance on the passing of one season to the next, holding "Fire Festivals" which were celebrated for three days (two days on either side of the day itself).
One of these festivals was called Samhain (pronounced Sha-Von) and it took place on October 31 through to November 1. During this period, it was believed that the boundaries between our world and the world of the dead were weakened, allowing spirits of the recently dead to cross over and possess the living.
In order to make themselves and their homes less inviting to these wayward spirits, the ancient Celts(凯尔特人)would douse (插入水中, 把弄熄, 弄湿)all their fires. There was also a secondary purpose to this, after extinguishing all their fires, they would re-light them from a common source, the Druidic fire that was kept burning at Usinach, in the Middle of Ireland.
Samhain was considered to be a gateway not only from the land of the dead to the land of the living, but also between Summer and Fall/Winter. For the Druids, this was the last gasp (喘息, 气喘)of summer (it was also the Celtic New Year), so therefore they made sure it went out with a bang before they had to button down (把...弄清楚)for the winter ahead.
They would dress up in bizarre costumes and parade through their villages causing destruction in order to scare off any recently departed souls who might be prowling (巡游)for bodies to inhabit, in addition to burning animals and other offerings to the Druidic deities(神, 神性). It is also a popular belief that they would burn people who they believed to be possessed, but this has largely been debunked (揭穿, 拆穿假面具, 暴露)as myth.
This yearly festival was adopted by the Roman invaders, who helped to propagate (传播, 宣传)it throughout the rest of the world (and at that time, the Roman Empire was the world). The word "Halloween" itself actually comes from a contraction of All Hallows Eve, or All Saint's Day (November 1), which is a Catholic day of observance in honor of saints.
This tradition was later brought to the North American continent by Irish immigrants who were escaping the Potato Famine in their homeland. In addition to the festival itself, the immigrants brought several customs with them, including one of the symbols most commonly associated with Halloween -- the Jack 'O Lantern.
According to Irish folklore, there once lived a man named Jack who was known for being a drunk and a prankster(顽皮的人, 爱开玩笑的人). One night Jack tricked the devil into climbing a tree, and quickly carved an image of a cross on the trunk, trapping the devil. Jack then made him promise that, in exchange for letting him out of the tree, the Devil would never tempt him to sin again. He reluctantly agreed, but was able to exact his revenge upon Jack's death. Because of his mischievous ways in life, Jack was barred from entering heaven and because of his earlier trick, he was also barred from hell. So he was doomed to wander the earth until the end of time, with only a single ember(灰烬, 余烬) (carried in a hollowed out turnip.[植]芜箐, 芜箐甘蓝) to warm him and light his way.
万圣夜的主要活动是"不给糖就捣乱"(Trick-or-treating)。小孩装扮成各种恐怖样子，逐门逐户按响邻居的门铃，大叫:"Trick or Treat!"(意即不请客就捣乱)，主人家(可能同样穿着恐怖服装)便会拿出一些糖果、巧克力或是小礼物。部分家庭甚至使用声音特效和制烟机器营造恐怖气氛。小孩一晚取得的糖果往往以袋计算，整袋整袋的搬回家。
在苏格兰，小孩要糖果时会说:"The sky is blue, the grass is green, may we have our Halloween."(天是蓝色，草是绿色，齐来庆祝万圣节前夜)，然后以唱歌跳舞等表演来博得糖果。
研究机构 BIGresearch 曾为美国全国零售联盟进行调查，发现53.3%的顾客会为2005年万圣节前夜购物，平圴消费额38.11美元，较去年高10美元，以此推算，美国消费者为2005年万圣节支出的金额高达33亿美元。
此外，还有"咬苹果游戏"(bobbing for apples)，参加者设法只用嘴巴咬起漂浮在水上的苹果。