Tango is a major tourist attraction in Buenos Aires, certainly the activity you see most advertised to foreigners. Posters with "Learn Tango!" or "Free Tango Show!" can be seen throughout the city, it is a central facet of the Argentinian, and more specifically Buenos Aires, culture.
Tango, like it's evil cousin Salsa in Colombia, holds little appeal for me. That's probably partially based in the fact that I am terrible at all forms of dance, ((Except the classic Middle School Mixer Slow Song!)) but the fact remains. Tango might not be my thing, but such is the nature of travel. You're not going to love every city or activity, some things you'll find altogether uninteresting. Furthermore, there is beauty in the fact that there are always other places to go, other directions to explore.
Yet even though the dance itself is unappealing to me, it's ubiquity in Buenos Aires led me to unintentionally pick up a few facts the dance of the Argentinians. Here are two:
1. Argentinian tango is notably different than American tango. American tango is flashier (the rose in the mouth cliche), involves bigger steps, and is the type generally seen in dance competitions. Argentinian tango is more subtle and refined.
2. There are widespread disagreements about the origin of tango, but most agree that it had something to do with the brothels found throughout 19th century Buenos Aires. Specific theories range from the dance being something that men often did with with prostitutes (before jumping into bed), to the men dancing with each other in the street while waiting for prostitutes to become available, to it simply being a dance of the lower class and first popular in areas rife with brothels.