The station building in Lennestadt-Grevenbrück, which was listed in 1991, was reopened at the end of 2013 as the "KulturBahnhof" after several years of renovation. The station houses a restaurant ("EssBahnhof"), a branch of the registry office and exhibition or event rooms (e.g. for the permanent exhibition "Fahrt Richtung Zukunft. The Ruhr-Sieg route and the change of mobility", concerts at the Steinway grand piano, readings or wedding ceremonies).
Opening hours and admission prices vary depending on the event.
Here is more information: https://www.lennestadt.de/aktiv/Kultur/KulturBahnhof/Dauerausstellung.
By the way, the KulturBahnhof is located directly on the SauerlandRadring.