In Buenos Aires, the Nightlife starts at around 10 pm, to go to dinner or, for youngers, to go to pubs and bars and lasts along the night till the sun comes back again! The capital with European flavour and strong latin spirit, Buenos Aires, holds the passionate Tango in its heart!
There are many tango shows and venues to dance tango, you might dig the Piazzolla Tango in San Martin 170, in the district of San Telmo, or still the Gala Tango at Casa de Tango in Pasaje 5 de Julio 434, again in San Telmo. It's a unique place also for its architectural beauty and decor in French style and is the most glamorous venue for Tango in Buenos Aires!
Also for dancing you might check out the Cafe de Los Angelitos located in Rivadavia, at 2100 Avenue Esquina Rincon. As for dinner and shows check out the Madero Tango.
Tangorama is the show of Mora Godoy, successful in theatres worldwide, with excellent tango dancers. Restaurant is attended by Martiniano Molina, a famous argentinian chef, but here, the price is quite expensive!