National restaurant chain’s 40th birthday party includes new Concrete Mixer, systemwide day of giving, guest sweepstakes PRAIRIE DU SAC, Wis., June 24, 2024 /PRNewswire/ — In 1984, the Culver family opened a burger and frozen custard shop in the small town of Sauk City, Wisconsin. Forty years, nearly 1,000 restaurants and millions of loyal guests […]