you might see if there will be any more underground markets-
http://www.argentinaindependent.com/tag/underground-market/
I am not sure if they will resume these after the new year, but I would guess yes.
There are several other small brewers there, which is both good and bad- beer lovers know to go there, and argentines like the idea of similar businesses being clustered, but, of course, there is competition.
if you want to do a tasting all your own, there are many possibilities. tons of restaurants would probably do a special night.
depends on the crowd you want- art galleries are another possibility- something like slyzmud might be good- small, classy gallery, they serve beer and wine at their openings anyway, draw a hip, but classy crowd-
http://slyzmud.tumblr.com/
or, maybe Foster Catena in Palermo Soho, right in the thick of things-
https://www.facebook.com/pages/Galer%C3%ADa-Foster-Catena/132778303454638?hc_location=timeline
if you want to do something totally from scratch, hire Ideal Confiteria for a night, get a DJ, - amazing place, hosts hip private events. http://www.confiteriaideal.com/
really, it depends on your whim- there are dozens of event spaces, from funky to elegant, that you can do a deal with, or rent space from.