San Telmo: One of the oldest neighborhoods of Buenos Aires, San Telmo will meet every romantic's expectations: cobblestone streets, wrought iron balconies, antique markets and tango. The outskirts of San Telmo, away from the throngs of tourists, is a staging area for murga.
It's well worth spending a couple of days in Montevideo -- a three-hour ferry journey from Buenos Aires across the Río de la Plata. Carnival here is under way and continues into early March.
Teatro de Verano: It's one of the most important venues for official murga competitions, but smaller open-air tablados also host cheap murga performances throughout the carnival season. It's best to buy tickets well in advance, especially if you're planning to see the top acts compete in the finals.
Barrio Sur and Palermo: Candombe drumming performances and llamadas, a call-and-response procession or parade, occur in these traditional Afro-Uruguayan neighborhoods. Like murga, they are central features of carnival, but you generally don't need a ticket.
Museo del Carnaval is a great place to learn more about the history of murga and other carnival traditions. The museum can also recommend venues for murga, candombe and llamadas.