I wanted to go there in years, but never managed to actually do it, despite it is in the city where I work: the Kaiserpfalz-Museum in Forchheim. The Museum houses the archeological collection of the region plus a section on the history of Forchheim in newer times.
The Kaiserpfalz is the old castle, from the times when Forchheim still was a place you could find on a map. The city used to be be one of the stations the german Kaisers went to during the middle ages. The castle still has some nice murals from the 16th century, which you can see on the walls of the collections rooms.