it's interesting to me that halloween breeds hyper-local activity clusters in the exact opposite way that most are built. Protests, marches, etc. target large, well-travelled areas first, but trick-or-treaters favor the opposite -- the less likely a car is to drive down a road, the more likely it is to have trick-or-treaters on it. Yet two blocks away, you can have dead silence. Hastings Square was so crowded you couldn't actually walk down the street, but Kenwood St. had more candy, and had nobody at all.