Hola! The really rocking playground in Puerto Madero is at the intersection of Avenida Rosario Vera Penaloza y Avenida Calabria. The playground is on one side of the avenue if you cross the street and go through the big hedges, there's another place space with a zipline, super fun! If you keep heading towards the water, there's a big feria (maybe only on the weekends, not sure) and in the middle are trampolines and jumpy houses you can rent for ten minute stretches, also fun. You're also not far from the entrance to the Reserva from there, if I'm not mistaken.
Check out Parque Lezama, big old school playground with a carousel and lots of possibilities for riding a bike or scooter, in San Telmo.
Another fun trip is Parque Los Andes, a nice park with two playgrounds not too far from El Galpon, the organic market in Chacarrita. We made a fun day trip of going to the market Saturday and making our purchases, then going to the park to play and then back to the market to pick up our stuff. (I don't know what you call that system, but I was so glad I read about it before I went or I would have been so confused--you select what you want from different vendors, then go to the register to pay for everything, they stamp your receipt and then you go back to the vendor to pick up. Not so efficient in terms of time and more challenging with kids, but oh well, at least we didn't have to lug everything to the playground with us...)
My son also likes going to the cemeteries and asking about all the dead people. (Weird, but at least we're outside and moving, and contained) Recoleta is a nice trip for that and you can visit Proohibido No Tocar at the same time, and there's a small but very nice playground at one end of Plaza Francia.
Three smaller playgrounds in Palermo that we've enjoyed are:
1) playground in Parque Las Heras--equipment not so nice, but lots of sand
2) Plaza Salguero, especially in summer, lots of kids and shade for the steamy afternoons
3) don't know the name of the plaza, but the intersection is Castex y Gelly. There's a nice wooden playground there.
I don't know what it's called, but there's a big lake in Palermo with one entrance at the intersection of La Pampa and Castaneda, Palermo-Belgrano, I'd say, and while there's no playground, the lake makes a nice circuit on a bike or scooter or slow walk, depending on your kids. The road around it is closed to traffic on the weekends, and there are paddle boats to rent on the weekends. I've also seen little ponies for rent for smaller kids. The 130 drops you at one end.
I love the Reserva Ecologica del Sur and am planning to check out he one in Vicente Lopez and also Parque Leloir, which is supposed to be a great place for kids to ride bikes and also has a reserva, but we've got to mobilize some friends with cars for that, I think.
It's been the biggest challenge for me living here, actually, coming from San Francisco where great playgrounds and nature are in abundance and easily accessible, trying to find open air activities, but many of the playgrounds in Capital have improved enormously in the last three years. I'd love to hear what others have discovered!
happy playgrounding!
Julie