http://www.festivalbuendia.net/
Saturday December 19th 2009
Plaza Palermo Viejo (Costa Rica, Armenia, Nicaragua, Malabia)
12:00 - 24:00

One of the most liberating (its free) music festivals welcoming summer and the end of the year in the Americas. Design, music, art, and plenty of charisma all surrounding a backdrop of youth. Check out the above link and the lineup. Did I mention its free. Buenos Aires at its most glorious.