Here are some good ideas that i could think of...

-- Gauco Party: This gives you the chance to see a real Argentine estancia and see what it was like being a gaucho. Great food, great music, and a lot of fun! Definitely something that not everybody experiences when they come here.

-- Tango Show: I'm not talking about the overly touristy shows or the free ones they put together in the street. If you go to BA, the birthplace of tango, you need to see a real, professional tango shows at an one of the old-school estancias around the city. Also, nothing compliments tango better than a great dinner and a fine glass of malbec wine!

--Tigre: This is where the porteņos go on weekends. It's beautiful, with the river and the delta. The boat rides are incredible and romantic, and the crafts fair is authentic and reasonably priced. This is perfect for a breath of fresh air away from the big city, and it is so easy to get to.