Treinta y Tantos is an absolute must for anyone passing through Concepcion.  The name means "thirty-something" and refers to the number choices of empanadas available at the restaurant.  One empanada will do for a light dinner, and two if you are hungry, and at about $1.50 each, are a great deal.  The restaurant also serves alcohol, with wine and Pisco Sours the favorites.  This restaurant is appropriate as the destination for a low-key night out, or as the precurser to an all-night outing at one of the nearby night clubs.