From the original patch notes in 2005:
“When the decorations of Hallow’s End light up Azeroth’s cities, you know there’s mischief afoot! Seek special vendors in Orgrimmar or Ironforge and get your hands on treats! Aid a sick orphan in a little trick-or-treating! Darkcaller Yanka, attending the Forsaken’s Wickerman Festival, and Sergeant Hartman of Southshore are seeking your aid in keeping the enemy out of their holiday affairs - are you up to the challenge?”
Hallow’s End will . . . end on November 2.