Bumchin Tegshjargal and Michelle Klets, a pair of Bay Area 17-year-olds, spin onto the floor. He’s clothed in black from head to toe. She’s wearing a sparkly raspberry-colored dress. They take their ...

At 7:30 p.m. on a Monday, Andrej Hacke, an instructor for Princeton Ballroom Dance Club (PBDC), plugs his phone into the speaker of the Group Fitness Room in Dillon Gymnasium. Cha-cha-cha music ...