Explore the valley riding on the back of a horse, which can be arranged by your hotel or casa particular. No experience is necessary. The paths can be quite rough, but the horses are very capable (the locals call them "semi-automatic"). Depending on the amount of time you would like to spend there are several routes that your guide can choose. You will likely explore some of the sights in the area about 2-4 km around Viñales, stop at smaller caves or visit tobacco farms. Put on sunscreen in advance, wear long trousers, and bring plenty of water (although on longer trips you will stop at primitive cafes with amazing views).
In the central plaza, the Casa de la Cultura puts on events every day (or night), including music, fashion shows, and children's events.
Also on the central plaza is an art gallery and the church. On Saturday mornings there is a farmers' market at the plaza.
Perhaps the worst tourist attraction in Cuba. In 1961 Fidel Castro visited the beautiful "valley of the two sisters (Valley de Dos Hermanas). He commissioned a cliff to be painted with snails, dinosaurs, and a family of cavepersons, in garish colors! There is a restaurant, bar, and gift shop. The food in the restaurant is reputed to be excellent and the live music is good, and locals say that the piña colada in the bar is the best in Viñales. Also there is horseback riding. So consider visiting the mural and doing something other than looking at the mural. You do not have to pay the entrance fee to see the painted mountain cliff, its visible from the road.
To learn about tobacco farming, visit this tourist-oriented tobacco farm and drying shed. Food is also served.
Zipline totaling 1100 meters across four stages, located 7 km west of downtown Viñales. Next to it is a hilly area featuring a number of wooden statues, a lake and a viewing platform of the valley, which costs a few hundred pesos to enter.
An easy to visit cave well-developed for tourists, featuring a boat ride through the cave. Nearby is a restaurant, gift shop, etc.