I've "heard" a couple times that it's a holiday based off of the fall of Atlantis.
Google search results yield this as the first site:
"Halloween originates from the destruction of Atlantis on November 1, about 12,500 Years Ago (11/1). The eve of this was October 31. Their fate being sealed, many Atlanteans had an ALLOWING. Where they allowed themselves to have fun despite their fate. Allowing became Halloween. There became an air of: “dine and be merry because tomorrow we die”."
http://www.creationislove.com/happy-allowing-halloween/
"So as you celebrate Halloween year after year, know and feel the energy from it’s true origin; the “allowing” prior to Atlantis final destruction. And also choose wisely as you select those who decide your fate as we symbolically start anew every November second by holding our elections. So Boo!….Happy Halloween!"
Google search results yield this as the first site:
"Halloween originates from the destruction of Atlantis on November 1, about 12,500 Years Ago (11/1). The eve of this was October 31. Their fate being sealed, many Atlanteans had an ALLOWING. Where they allowed themselves to have fun despite their fate. Allowing became Halloween. There became an air of: “dine and be merry because tomorrow we die”."
http://www.creationislove.com/happy-allowing-halloween/
"So as you celebrate Halloween year after year, know and feel the energy from it’s true origin; the “allowing” prior to Atlantis final destruction. And also choose wisely as you select those who decide your fate as we symbolically start anew every November second by holding our elections. So Boo!….Happy Halloween!"