It was 1979 and Steve Benko was one year into his job as New Canaan’s recreation director when the town started talking to Manhattan-based Music Performance Trust Fund, a recording industry nonprofit dedicated to promoting live music. That organization worked through local unions to line up bands for live performances in towns such as New Canaan, splitting the cost of a show 50-50, Benko recalled. New Canaan had recently held a successful U.S. Coast Guard Band concert at Waveny, off of the expansive balcony behind the main house, and so the town moved ahead with the nonprofit for a series of four shows in the summer of 1980—the first season of a series that’s emerged as fun, beloved tradition for New Canaanites each summer. “A lot of people say it’s the best kept secret in New Canaan, because people don’t realize it’s there,” Benko said Tuesday from his second-floor office at Waveny House, overlooking that same balcony and sprawling fields below. “It’s a fun evening.