I was expecting to find more to your question. That said, Hallowe'en is about different things to different cultures. Here in Australia, it has long been frowned upon as something "American." In recent years it has gained quite a following, with trick or treating becoming more and more popular amongst children.
In reality, it marks All Hallows' Eve, and is said to be the one night of the year that the spirit world and the living collide. Despite it being associated with the US, All Hallow's Eve comes from Europe.
Watch out for the Great Pumpkin!