Halloween doesn't really work in New Zealand.
Sure, every year there's a few more kids knocking on our door, dressed as vampires or Munch screams or princesses*. But in October it's still light in the evenings and the temperature is more suited to a quick swim at the beach than hiding while evil spirits roam, etc.
Halloween seems to be working just fine in Wales and Germany:
Cops coax half-naked Czech wolfman from Cardiff tree
Drunk zombie mistaken for murder victim
And now if you'll excuse me, I have an appointment with all that uneaten candy sitting in a bowl by the door...
* Don't think a princess is scary? I've got two little girls. I'm scared of ponies.