I find lots of things I love in BA.
But I find lots of things interesting wherever I go- just weird that way, I guess.
In Buenos Aires, I like the music, myself- there is a whole thread here about music,
http://baexpats.org/newcomers-forum/5674-great-argentine-bands.html
lots of different opinions are expressed.
I second the recommendation of Konex on monday nights- they always have a different guest musician with the drummers- could be a jazz horn player, or a choir, or a DJ.
Also, I always enjoy CAFF- kind of the argentine equivalent of "Americana" style bands in the USA like Wilco or Neko Case.
http://www.fernandezfierro.com/caff/
Its cheap, not a pickup scene, and no crowds of drunken laddettes.
Thelonius always has good jazz.
If all the DJ's sound the same, check out Zizek- they are a group of DJ's who make their own music, so it all sounds unique. At Niceto sometimes, or other venues.
http://www.zzkclub.com/
Two of argentinas most interesting musicians, Gaby Kerpel and Axel Kreiger do their DJ thing with Zizek.
I usually check whatsupBuenosAires for the options of the night- music, art, and other stuff.
BA is a great film town as well. The best is when BAFICI is on, in April-
http://www.bafici.gov.ar/home/web/en/index.html
468 films in a little over a week. Most are foreign, lots in english with subtitles.
Last year, we saw 3 Chaplin silent shorts, each with a different argentine band improvising a soundtrack to it- it was great.
But the arteplex theaters always show interesting stuff-
http://www.cinesarteplex.com/encartel-abelgrano.php
The various cultural centers, all around town, usually have interesting film, art, and performance-
Recoleta, next to the cemetery, or on Florida upstairs from the Galleria Pacifico, are two good ones, but the government pays for a good half dozen in BA.
There is a cool little observatory in Parque Centanario-
http://en.wikipedia.org/wiki/Parque_Centenario
I think its free on weekend nights. You can look at stars.
I am a big museum hound, and there are some very cool museums here- Xul Solar, for example, which looks like an ordinary house on the outside, inside, its a wacky Escher print come to life, and Xul Solar himself lived there til he died.
Or the museum in the waterworks on Cordoba, with its hall of toilets.
The arms and armor museum, in Retiro- in a classic palace, full of swords and guns of unbelievable splendor.
The Che Guevara museum is supposed to be pretty fun.
http://www.buenosaires-argentina.com/attractions/museo-ernesto-che-guevara.html
Or, go to Tierra Santa- the cheezy religious theme park- where the mechanical Jesus is resurrected every 18 minutes.
I have it on good authority that the worlds largest hairball is lurking in the pool at Punta Carrasco- I would consider an expedition to see that, myself.
I like to take the collectivo out to the Chacarita Cemetery- its not touristy at all, its bigger than the Recoleta Cemetery, and its a whole city of the dead. Usually, on weekdays, its practically empty.
Just outside, around the parque Los Andes, on Corrientes, is a great flea market on Saturday afternoons- need Power Ranger pajamas, or fake fur mushroom shaped hassocks, or incense or shoe repair or cheap glitter thong underwear? Or junk from a hundred attics and garages? Along with cheap munchies, of course.
Pretty much anything at La Rural is fun. La Rural itself, in July, the actual nationwide county fair, is the best- Giant Cows!
But the book fair, or ArteBA, or Caminos y Sabores, or the Artisan fair in December are all pretty great too. Me, I like the weird industrial trade shows as well.
I like taking the subte or collectivo to a new, non-tourist neighborhood, and just walking around.
A great resource for this is Robert Wright's website-
http://www.wrighton.com.ar/
I am working my way thru this book as well-
http://www.littlebookroom.com/authenticbuenosaires.html
the places in this are the real buenos aires- cheap, authentic, and usually pretty decent eats, too.