31 October and 1 and 2 November are called, colloquially (not officially), "Hallowtide" or the "Days of the Dead" because on these days we pray for or remember those who've left this world.

The days of the dead center around All Saints' Day (also known as All Hallows') on November 1, when we celebrate all the Saints in Heaven. On the day after All Hallows', called "All Souls' Day," we remember the saved souls who are in Purgatory, being cleansed of the temporal effects of their sins before they can enter Heaven. The day that comes before All Hallows', though, is one on which we unofficially remember the damned and the reality of Hell. The schema, then, for the Days of the Dead looks like this: 

The earliest form of All Saints' (or "All Hallows'") was first celebrated in the 300s, but originally took place on 13 May, as it still does in some Eastern Churches. The Feast first commemorated only the martyrs, but came to include all of the Saints by 741. It was transferred to 1 November in 844 when Pope Gregory III consecrated a chapel in St. Peter's Basilica to All Saints (so much for the theory that the day was fixed on 1 November because Irish pagans had harvest festivals at that time).

All Souls' has its origins in A.D. 1048 when the Bishop of Cluny decreed that the Benedictines of Cluny pray for the souls in Purgatory on this day. The practice spread until Pope Sylvester II recommended it for the entire Latin Church.

The Vigil of -- i.e., the evening before -- All Hallows' ("Hallows' Eve," or "Hallowe'en") came, in Irish popular piety, to be a day of remembering the dead who are neither in Purgatory or Heaven, but are damned, and these customs spread to many parts of the world. Thus we have the popular focus of Hallowe'en as the reality of Hell, and hence its scary character and focus on evil and how to avoid it, the sad fate of unsaved souls, etc.

One hears too often from the secular world that "Hallowe'en is a pagan holiday" -- an impossibility because "Hallowe'en," as said, means "All Hallows' Evening" which is as Catholic as it gets. Some say that the holiday actually stems from Samhain, a pagan Celtic celebration, or is Satanic, but this isn't true, either, any more than Christmas "stems from" the Druids' Yule, though popular customs that predated the Church -- such as the use of holly to decorate -- may be involved in our celebrations (it is rather amusing that October 31 is also "Reformation Day" in Protestant circles -- the day to recall Luther's having nailed his 95 Theses to Wittenberg's cathedral door -- but Protestants who reject Hallowe'en because pagans do things on October 31 don't object to commemorating that event on this day).

Hallowe'en customs are a mixture of Catholic popular devotions, and French, Irish, and English customs all mixed together. From the French we get the custom of dressing up, which originated during the time of the Black Death when artistic renderings of the dead known as the "Danse Macabre" were popular and meant to convey that death comes to each and every one of us, no matter our station in life. These "Dances of Death" were rendered in paintings and frescoes, typically depicting people from Pope to King to peasant dancing with or being surrounded by skeletons. This genre was also acted out by people who dressed as the dead -- nervously, comedically, to "laugh in the face of death" and for a sense of relief from the nightmarish reality of the plague that felled at least a third -- and possibly up to 60% -- of the people living in Europe. These danse macabre customs were moved to Hallowe'en when the Irish and French began to intermarry in America.

From the Irish come the carved Jack-o-lanterns, which were originally carved turnips. The legend surrounding the Jack-o-Lantern is this:

There once was an old drunken trickster named Jack, a man known so much for his miserly ways that he was known as "Stingy Jack," He loved making mischief on everyone -- even his own family, even the Devil himself! One day, he tricked Satan into climbing up an apple tree -- but then carved Crosses on the trunk so the Devil couldn't get back down. He bargained with the Evil One, saying he would remove the Crosses only if the Devil would promise not to take his soul to Hell; to this, the Devil agreed.

After Jack died, after many years filled with vice, he went up to the Pearly Gates -- but was told by St. Peter that he was too miserable a creature to see the Face of Almighty God. But when he went to the Gates of Hell, he was reminded that he couldn't enter there, either! So, he was doomed to spend his eternity roaming the earth. The only good thing that happened to him was that the Devil threw him an ember from the burning pits to light his way, an ember he carried inside a hollowed-out, carved turnip.  

And when you carve up your pumpkin, keep the seeds to roast (recipe here).

From the English Catholics we get begging from door to door, the earlier and more pure form of "trick-or-treating." Children would go about begging their neighbors for a "Soul Cake," for which they would say a prayer for those neighbors' dead. Instead of knocking on a door and saying "Trick-or-treat," children would say either:

A Soul Cake, a Soul Cake,
have mercy on all Christian souls for a soul cake!

or

Soul, soul, an apple or two,
If you haven't an apple, a pear will do,
One for Peter, two for Paul,
Three for the Man Who made us all.

While Soul Cakes were originally a type of shortbread, it is said that a clever medieval cook wanted to make Soul Cakes designed to remind people of eternity, so she cut a hole in the middle of round cakes before frying them, thereby inventing donuts! Fresh plain cake donuts would be a nice food to eat on this day.

Nowadays, trick-or-treating typically results in being given candy -- or handing it out if you got old.

Other customary foods for All Hallows' Eve include cider, nuts, popcorn, and apples -- best eaten around a bonfire or fireplace, of course (bonfires are traditional tonight, just as they are on the Feast of St Lucy, St. John's Eve, Walpurgisnacht, Holy Saturday, Candlemas, and other feasts). And there is, of course, Irish Barmbrack, a sultana-studded yeast bread traditionally baked with trinkets inside that fortell one's fortune for the coming year (recipes for both cake donuts and barmbrack here).

Another Hallowe'en custom is the old Celtic "bobbing for apples." To do this, fill a large tub two thirds full with water and float apples in it. Children take turns trying to pick up one of the floating apples using only their mouths (hands are not allowed and must be held or tied behind the back!) -- very tricky to do! The first to do so wins a prize (some say he will be the first one to marry someday). You can make the game more fun by carving an initial into the bottom of each apple, letting that initial indicate the name of the person each apple-bobber will marry, and/or using different colored apples with different assigned meanings or prizes. (You can play a dry version of this game by tying the stems of the apples to strings and suspending them. If you do this, carve any initials at the tops of the apples). You can find other games to play here (pdf), including Hallowe'en Bingo, for which I've made Bingo cards for you.

Perfect for the day, too, are scary stories! If you want great poems and stories to relate to your children on this day, try these, which you can download in pdf format: 

The Monkey's Paw, by W. W. Jacobs (9 pages)
The Cats of Ulthur, by H. P. Lovecraft (3 pages)
The Sandman, by E.T.A. Hoffman (20 pages)
The Lottery, by Shirley Jackson (7 pages)
The Tell Tale Heart, by Edgar Allan Poe (4 pages)
The Cask of Amontillado, by Edgar Allan Poe (7 pages)
The Tower, by Marghatina Laski (6 pages)
The Empty House, by Algernon Blackwood (12 pages)
The Legend of Sleepy Hollow, by Washington Irving (20 pages)
The Body Snatcher, by Robert Louis Stevenson (14 pages)
The Mark of the Beast, by Rudyard Kipling (10 pages)
The Yellow Wallpaper, by Charlotte Perkins Gilman (15 pages)
The Landlady, by Roald Dahl (8 pages)
Scary Poems (36 pages) This pdf includes:

Little Orphant Annie, by James Whitcomb Riley
The Little Ghost, by Edna St. Vincent Millay
The Night Wind, by Eugene Field
The Witch, by Mary Elizabeth Coleridge
Antigonish (I Met a Man Who Wasn't There), by Hughes Mearns
The Raven, by Edgar Allan Poe
The Stolen Child, by William Butler Yeats
The Wreck of the Hesperus, by Henry Wadsworth Longfellow
The Highwayman, by Alfred Noyes
The Pied Piper of Hamelin, by Robert Browning
The Listeners, by Walter De La Mare
This Living Hand, Now Warm and Capable, by John Keats
The Drowned Man, by Alexandar Pushkin
The Haunted Oak, by  Paul Laurence Dunbar
The Dance of Death, by Charles Baudelaire
Darkness, by Lord Byron

Another option is to listen to Old Time Radio shows, a selection of twenty-one of which I provide below in mp3 format. I highly recommend your listening to them first before allowing your children to listen to them; though old, some may be more adult or more intense than would be good for your kids, whom you know better than I (the shows from the "Dark Fantasy" series are unintentionally hilarious while trying to be scary; I couldn't resist including them!).

And there are, of course, recorded recitations of scary stories and poems. A selection for you, all in mp3 format:

Perhaps a backdrop of Bach's Toccata and Fugue in D minor (BWV 565) might help you set the scene. This piece wasn't written for Hallowtide, but its ominous tones invoke horror:

Or maybe scary sound effects are what will make your Halloween party a good one. Here are 8 hours' worth of scary sounds from the Fantasy Realm Youtube channel:

After teaching your children about the frightening realities of Hell, the fate of the damned, and giving them a good, fun, appropriate-to-their-level-of-maturity scare, reassure them by telling them that the Evil One has already been conquered! He can tempt, obssess, and oppress us, but Satan has no ultimate power over those who are in Christ, and mocking him and his minions is a way of demonstrating this; teach your children how to call on the power of Christ and His Church to protect themselves from the Evil One's snares. Warn them that magick (the art of performing actions beyond the power of man with the aid of powers other than the Divine) is real, that there is no such thing as "white magick," that playing with the occult -- whether by divination, necromancy, the casting of spells, playing with Ouija boards, etc. -- is an invitation to demons to respond, and that it is from demons that magick gets any power it has. Remember St. Michael to them, teach them about the power of sacramentals and prayers that ward off evil when piously used (the Sign of the Cross, Holy Water, blessed salt, the Crucifix, the St. Benedict Medal, St. Anthony's Brief, etc.), teach them to call on the Holy Name of Jesus when they are afraid, etc.

P.S. Remember! If you made apple dolls on Michaelmas, now is the perfect day to unveil and decorate them. They tend to look a little spooky!