For some families, it's not Thanksgiving without grandma's sweet potato pie. For families like Leigh Odom's, it's not Thanksgiving without an after-dinner strategic ops planning session: Shopping lists are itemized, routes are mapped out and a game plan is formed, all with military-like precision. Because after dinner, it's no longer Thanksgiving. It's Black Friday Eve.

To those who spend the Friday following Thanksgiving doing things like spending time with family, or working, or volunteering, or attempting to construct the world's greatest turkey leftover sandwich, Black Friday devotees are a mystery. Yes, an estimated 147 million Americans plan to go shopping sometime this weekend, according the National Retail Federation. But who are these people, what's the psychology driving them to rise before dawn in pursuit of a deal -- and have they really never heard of online shopping?

"The deals are part of it, but I don't think it's the bigger piece of it," says Jane Thomas, a professor of marketing at Winthrop University in Rock Hill, S.C. "This is the family ritual, as much as eating turkey and dressing is -- it's going shopping as the start of the holiday season together."

Last year, Thomas and her Winthrop colleague Cara Peters published a study in the International Journal of Retail and Distribution Management that sought to explore those rituals that have sprung up around Black Friday, in order to understand more about this intense subculture and its disciples. Over two years they conducted interviews with 38 "experienced female Black Friday shoppers." (They stuck with women-only because it tends to be the females of the family who handle holiday traditions, including shopping, they explain in the report.) And they found something kind of surprising: Interviewees repeatedly used military metaphors to describe their Black Friday adventures -- the strategic planning, the mission accomplished, and the subsequent bonding with your fellow survivors. This is how seriously these families take it.