The Subte Linea A- Here you can ride on beautiful but somewhat distressed antique wooden subway cars.
Feral Cat Watching- BA has two great sites for this. The first is the famous Reccoleto cemetery, which is as wonderful as all the guidebooks say. Wandering amid the crypts, statuary and beaux-arts mausoleums are hundreds of well fed looking stray cats. The Jardin Botanico is a more pastoral setting for feral felines. Here scrawnier looking cats wander and fight in the shadows of exotic vegetation.