Black Friday 2011

Philadelphia police and bus drivers call it "Black Friday" - that day each year between Thanksgiving Day and the Army–Navy Game. It is the busiest shopping and traffic day of the year in the Bicentennial City as the Christmas list is checked off and the Eastern college football season nears conclusion.
The derivation is also clear in an Associated Press article entitled "Folks on Buying Spree Despite Down Economy," which ran in the Titusville Herald on the same day:
Store aisles were jammed. Escalators were nonstop people. It was the first day of the Christmas shopping season and despite the economy, folks here went on a buying spree. ... "That's why the bus drivers and cab drivers call today 'Black Friday,'" a sales manager at Gimbels said as she watched a traffic cop trying to control a crowd of jaywalkers. "They think in terms of headaches it gives them."
The term's spread was gradual, however, and in 1985 the Philadelphia Inquirer reported that retailers in Cincinnati and Los Angeles were still unaware of the term.