As per museums, there's the children’s museum called Maine Discovery Museum on Main Street. There is also a Bangor Police Museum, but one can only view it by making an appointment by calling 207/947-7384, Monday through Friday 8am to 5pm. It has hundreds of police items, including a one-person cell chair.
The Museum of Art on the University campus (the University of Maine is situated in the neighboring town of Orono) holds regular exhibits. For a calendar of events, check www.umma.umaine.edu.
The Cole and Land Transportation Museum is home to many WWII articles, including a small replica of a helicopter and a tank. They are only open during the summer season, starting in May.