Who Dat?

Right, so on arrival to New Orleans - I was overwhelmed by a huge amount of merchandise and signs all over the place saying "Who Dat?". I thought perhaps it was a "I'm In Miami Bitch!" merch type thing, but turns out it's.. umm.. far more sensible.
"Who Dat!?" (according to my taxi driver, and Wikipedia) is: is a chant of team support, used especially by fans of the New Orleans Saints, an American football team.
My taxi driver informed me this team won a championship last year - and "Who Dat?!" is part of their winning chant by fans. The Saints are actually playing this weekend - which also happens to be Halloween weekend - hence the strange combo of skulls, skeletons and.. WHO DAT?!