If you can, go to a San Lorenzo game instead of Boca Juniors, the fans there are more passionate and there is a better atmosphere.
Bonbonera is nice but nothing compared to this.
http://www.youtube.com/watch?v=MUliw5qHilg&feature=relmfu
http://www.youtube.com/watch?v=HdcRYEybfmI&feature=related