Harvard dialect study and TP'ing vs. rolling
A group of Harvard linguists has released a set of maps from their dialect study of American English. The study is based on self-reporting (you can register and take the survey yourself if you like) so I don't know what its scientific value is, but it's certainly interesting to poke around in. You can see maps for the pronunciation of classic shibboleths like aunt or creek, or less familiar ones like "the act of covering a house or area in front of a house with toilet paper".
Oddly, this last one shows a more clear-cut geographic distribution than any other map I browsed, with "rolling" being predominant from Louisiana to South Carolina, "tp'ing" or "toilet papering" most common elsewhere. I've never heard of "rolling" a house in my life. One more piece of evidence that Texas is not part of the South (praise "Bob"!).