This was so much fun! You take a tram to the top of the mountains then zip down 6 different 1/2 mile long cables back to the bottom. I think there's only two main companies that offer this but Sky Trek is the better qualify company. Your hotel should be able to help you book with them.
They have their own hot springs so there's no need to pay like the other springs in the area. The resort has a variety of activities (with a cost). I did the canopy tour through the rainforest (HIGHLY recommended) and the horse back riding tour to the volcano. The instructors at the canopy tour are a riot. A fun group of guys.
Near the town there is a small but really nice natural park.
The area around the town was destroyed by the volcano 30 years ago, but nature follows its way, and now the place shows incredible views like these waterfalls. If you are brave enough you can try to take a bath under the falls.