The Buenos Aires Museum of Modern Art is worth a visit while you are here. It boasts a large collection of art and is situated on the main street of San Telmo: 350 San Juan Avenue. Entry is free.
In the nighttime, this area comes alive with an underground dancing, restaurant and club scene. Some good Tango bars where they offer free classes can be found here. Remember to sample some parillas, where they make meat-filled Argentinian delicacies.