In about a month and a half it'll be Halloween. I just want to remind all of you that contrary to pop history, Halloween is not a pagan holiday, it's a Christian holiday, the eve before All Saints Day, and the beginning of Hallowmas.
The date chosen for All Saints Day (November 1st) was not chosen to supplant the pagan Celtic festival of Shamhain, this date for the feast of All Saints actually originated in the German Church during the 7th century and the Irish Church celebrated the feast of All Saints on April 20th well into the 8th century until Pope Gregory III made the German date for the feast the official date in the west and it featured much more prominently in celebrations in the Holy Roman Empire than it did among the Celts until the 16th century.
Trick-or-treating evolved from guising/souling, a custom that children in England, Scotland, and Ireland would practice during Hallowmas by going door to door in disguises to offer prayers for a deceased person's soul in purgatory in exchange for food or money. Children wore costumes to represent the souls in purgatory, not to scare away demons, fairies, ghouls, ghosts, or trolls. Admittedly when the Irish brought this practice to America many children would threaten and sometimes carry out a pranks against neighbors who didn't take up their offer (hence the phrase "trick-or-treat" and also the origin of Mischief Night being on October 30th) but eventually the phrase became harmless and apart of the tradition.
Jack-o'-lanterns originated from the Irish folktale of Stingy Jack. As the tale goes, Stingy Jack was an awful drunk who enjoyed playing tricks on everyone. One day, he tricked the Devil himself into climbing an apple tree. When the Devil climbed the tree, Jack placed crosses around the tree so the Devil couldn't come down. He made the Devil promise he wouldn't take his soul and when the Devil promised this he let him come down from the tree. Many years later Jack died. He was confronted by St. Peter at the gates of heaven who denied him entry due to his sinful life of drinking. But Jack told him that it was impossible for him to go to hell since the Devil promised never to take his soul. St. Peter traveled to hell to inquire this from the Devil himself and the Devil confirmed this, announcing that he could not cause Jack's soul to be damned. St. Peter informed God about this and God placed Jack's soul in limbo, a dark abyss at a neutral point between heaven and hell where there was neither good nor bad nor pain nor pleasure. Jack asked the Devil if he could help him light the way, so the Devil tossed him a hot coal from hell. Jack had a turnip with him, as it was his favorite food, and he was able to carve it out and place the coal inside to light his way. Jack-o'-lanterns were placed outside to help light Stingy Jack's way during Hallowmas. Eventually when the Irish brought this practice to the Americas they switched to using pumpkins and gourds and other squashes from the original turnips and potatoes.
As we can see, Halloween is a firmly established Christian holiday that all Christians should partake in. There is nothing pagan about it. It is Christian. Have fun with it, pray during this time, especially for the deceased in purgatory, and to the saints in heaven for their intercession. Amen.