History lesson

Halloween, or All Hallow's Eve, is observed on October 31st, the eve of the Christian Feast of All Saints. Its origins are linked to the Celtic festival of Samhain (pronounced SAH-win or SOW-in), which is old Irish for "summer's end." I believe Roseanne Conner described it best:

Roseanne: "Halloween is the one night of the entire year where the veil is lifted between the living and the dead. And the dead return from Hell to walk the Earth. And we have to dress up like ghosts and goblins and stuff. To fake out the evil spirits. Or else they might carry us back to Hell with them!"

Becky: "So why do the dead people come back?"

Roseanne: "For the candy! There's no chocolate in Hell, that's WHY it's Hell!"

If you want to know more, wiki that shit!