Dragon boats tied up along the Perfume River in Hue. Tourists hire these to leisurely cruise up and down the river. Lunch and drinks are usually served. I've never done this (although the boats are pretty wonderful), but I have heard that it is actually a good way to visit the nearby tombs (see Tomb of Khai Dinh and Tomb of Minh Mang). Boat operators apparently live on the boats with their families. [NOTE: I say that, because I have noticed little kids gleefully playing on the boats and laundry drying on the railings during early morning walks down by the river].