If you have more days left in Hue, there are a couple of recommended excursions. One is to a spa in the outskirts of Hue. If you need to relax, this is the place for you. In the area there are several pools with natural warm water. Some of the pools are hotter than others. Most of the visitors are Vietnamese. There is a bar that serves drinks and food. If you want to visit this place, ask your hotel or one of the tourist agencies in central Hue, or rent a taxi.
If you need more action, you can visit the Demilitarized Zone. The DMZ is the area around parallel 17th. This is the area declared neutral on the Geneva Accords. If you buy one of the tours, you will visit some monuments and tunnels. The excursion will take you a full day.
If you want to go to the beach, you can go to the Thuan an Beach, 10 miles from Hue. On weekdays the beach is almost empty.