The class was born of a roving monthly club night that Mr. Heffington held in 2006 and 2007, where clubbers learned short routines as they nursed their beers. Some of the night clubbers have changed their habits. “This is becoming more serious for them,” said Mr. Heffington. The class inspired one member to start a marching band. Another wrote her master’s thesis on it. The class is so popular that people are often turned away. Mr. Heffington has added a second class on Sunday and a weeknight class.