Geezer Happy Hour for The New York Times

Every Friday night from September to May, a group of die-hard music fans gathers to dance to live bands at a nightclub in Ann Arbor, Michigan. Almost everyone is over 60.

“Geezer Happy Hour” is the latest iteration of a weekly, musical happy hour that has been happening on and off since it started in the early 1970s at a one-room bar called Mr. Flood’s Party. Over the years, the crowd has aged right along with the acts; some people have been coming to the shows for 50 years. It is organized by Randy Tessier, a 72-year-old University of Michigan lecturer and writing instructor who has played in rock and jazz bands since he moved to the city in 1972, back when it was the center of American counterculture.

The turnout on a recent Friday night was typical: a mix of hippies, activists, professors, townies, amateur musicians and an assortment of more than 100 seniors who simply cannot stop dancing. They were dressed with unselfconscious flair: There were fringed jackets and fedoras, western shirts and bowties, rainbow bandannas and braided beards.