Tafi Viejo [dead link] is a town in the Tucuman province in the Andean Northwest region of Argentina. It doesn't really have any tourist attractions, except for a private park called "Alpa Puyo" where you can spend the day practising sports, walking, or simply sunbathing surrounded by the lush, always-green foliage. The views of Tucuman City and the eastern plains and the Aconquija Hills are amazing both during the day and at night. The admission costs 2 pesos per person.
Besides, there are cabins, a restaurant and café open all day, a small zoo, and a museum.