Knock, knock! Trick-or-treat? Halloween is here, bringing a whirl of costumes, candies and carved pumpkins to porches across Canada. What began over 1,000 years ago as Samhain, a Gaelic harvest festival where people disguised themselves to scare off spirits, has become a night of playful scares. Tonight, streets come alive with people in costumes of every kind, from eerie classics to hilarious pop culture twists.