The first night I arrived to Montevideo, outside of my place I heard the rhythmic, powerful, and (at this time upon arrival) alarming pounding of hand drums. Since then I have heard this music, along with chorus singing, every weekend night and a few nights during the weekdays.
The type of music is called Murga, and is similar to a Carnival-type sound/atmosphere. Apparently the groups are allowed to be only 17 people strong, according to some, all male (which is changing these days), and they sing about current events. During the dictatorship of Uruguay in the 1970s the Murga groups were some of the most powerful voices of rebellion.
But also, these Murga sessions are a warm up for the big show of Carnaval in February (on the 5th to be exact). I am loving it already!
Here is a you tube clip of Murga: