Last week, the zombies were out in full force for the opening of the Woody Harrelson zombie movie Zombieland. Apparently they didn't get enough, because they were in Union Square for another Zombie Crawl—obviously they are practicing for Halloween or just want to get some more mileage out of their costumes.
There are many Zombie Crawls planned this month—here's one resource for more information on brain-eating fun.