While not a raging party town, Otavalo has several cozy bars and clubs. It's easy to find a place with a local group playing traditional Andean music. One of my favorite spots is Amauta Peña Bar (tel. 06/2922-435), on Calle Morales 522, near Modesto Jaramillo. A band performs there every night and there's a minimal cover, which you can use toward the purchase of your first couple of drinks.
For dancing, check out the Habana Club (tel. 06/2920-493), on Calle Quito and 31 de Octubre. For a more mellow, boho scene, try Casa de Arte Da Pinto (tel. 06/2920-058), on Calle Colón 410, between Bolívar and Sucre. This place features creative artwork on the walls, tables, and floors, and serves up pizzas, burgers, beer, and wine.