I'll admit it it, I'm a huge language geek (speaking five of them either fluently or with proficiency, and being able to babble a smattering of a handful of others), so this map is, while confusing, completely fascinating. Via JoeMyGod:
It shows the eight regional dialects of North America, as well as the individual sub-dialects found in places like Pittsburgh, Baltimore, and the Hamptons.
Neat. Full, massive, headache here.