I definitely want to check out the partying scene! i feel like i couldn't say I was in BA without going to some fun parties. I also know a little tango so a laid back dance group would be really fun as well and I'm generally up for any adventure whether it is going to a landmark in the city or the countryside so if you have any leads I would love to hear it
While you are looking for adventure visiting a landmark in the city, do not wear/show visible expensive things as cameras, since pickpockets tend to be interested in them. Also it is safer not to walk alone (in case you have things that might get stolen).
As a women it is good to go out in company rather than alone, as this will give you more opportunities to ignore guys who are too forthcoming. Not every guy understands a women has a will of her own.
For tango,
if you would be a beginner and you do not want to bother about dancing well, you could visit
http://www.lacatedralclub.com/ (Sarmiento 4006, best day is Tuesday) or
http://www.lavirutatango.com/ (Armenia 1366, best day is Friday). These are probably the 2 worst places to learn tango. However, they are very informal, there are a lot of young people and they are open almost every day. In La Catedral, there is no airconditioning, so around this time of the year it would be rather hot. In these places there may be (some elder) guys you should not directly accept an invitation to dance from.
If you want a place with young people and a high level of dance, go to Club Fulgor (Loyola 828) on Tuesday or Saturday, however if you are new, it may be hard to get invitations to dance.
Another informal place with a lot of young people (except on Saturday) is Villa Malcolm (Cordoba 5064, best day would be Sunday).
I gave recommendations for places where you will find young people, not for where there is a high dance level.
