There is a Whale Watching Museum in Samana, which provides a bit of history on the humpbacks and their lives. It is small, and as such I can't seem to find a website for them, but if that's an interest, you might do a bit more searching on the web for that.
Other than that, a trip to Santiago, where the excellent Centro Leon museum, an art and anthropology museum, and the Folklore Museum are both located.