the toilet museum is always a hit-
https://turismo.buenosaires.gob.ar/en/atractivo/palacio-de-aguas-corrientes-water-palace
Bomba Del Tiempo Monday nights at Konex- its all ages, although there will definitely be some wacky tabacky fumes blowing by. A drum based, early outdoor concert that has 1000 people dancing and having fun. I always take people there- its infectiously likeable.
https://www.cckonex.org/espectaculo/la-bomba-de-tiempo/
late night choris or bondiolas from a cart on the costanera in Puerto Madero is fun and cheap.
Or fancy modern gourmet choris from XChori, now in 3 locations.
Ride the free trolley just off Rivadavia in Caballito on weekend evenings- its a time travelling trip thru a neighborhood of grand old art deco houses, with volunteer conductors and ticket takers. Usually mostly railfans and kids, not too many tourists.
https://turismo.buenosaires.gob.ar/en/article/caballito-historic-tramway
I also really like the Xul Solar musuem in Recoleta, and the tour of Palacio Barolo.
And while Cementario Recoleta is a bigger tourist draw, Cementario Chacarita is bigger, emptier, and has just as many wonderful miniature architectural masterpieces of tombs, and its right across from Pizza at Imperio. You cant visit BA without having fugazeta and faina.
scary and sobering, but really well done, is the museum at ESMA. last stop for the disappeared, before they were dropped in the Atlantic.
elegant jazz/funk/cumbia, with ping pong and foosball, tuesday nights at La Grande, Santos Dumont 4040. Again, its all ages- you see kids under 10, old people like me, old rock nacional stars in their 50s, and lots of kids from 20 to 40, dancing, sipping cocktails, slugging down craft beer, and eating the 2 entrees of each night, one always vegetarian, plus the music is always great, and always has different guest artists. But it may not be running in late December- they take a month or so off at the end of the year.