I found the Buenos Aires futbol amigos on tripadvisor and on my first day in BsAs I decided to pass by for more info. The place is a little hard to find (make sure you know street and nr), but once in I got a very warm welcome from Dave. But no time yet to ask for more info, they directed me to the pitch to first play futbol:-)
After the games they stay for a few beers, so great to meet some locals when you're new town. Highly recommended to all futbol amigos going to BsAs!