Tango in Madrid:
If you want to take tango lessons or dance, I know there are the following places...
Milonga el Abrazo: Thursday 9pm to 10 pm, Sala Central Park, Menéndez Pelayo Protected content of the hospital). Metro Ibiza. Class costs 12 euros and if you get 4 lessons you get them by 40 euros (so 10 instead of 12 euros per class). Here more information: Protected content
Milonga Bien Porteña: Friday , 7pm til 8 pm, takes place in Casa de Guadalajara, in C/ Plaza Santa Ana Protected content floor (Metro Sol). Class costs 12 euros and if you get 4 lessons you get them by 40 euros (so 10 instead of 12 euros per class). Here more information: Protected content
Milonga del Centro: Saturday: Friday , 8pm til 9 pm, takes place in Casa de Guadalajara, in C/ Plaza Santa Ana Protected content floor (Metro Sol). Protected content
Milonga "is a term for a place or an event where tango is danced. People who frequently go to milongas are sometimes called milongueros. The term "milonga" can also refer to a musical genre" says Wikipedia.
If you already know some tango or if you want to see people dancing, you can go to any of the places mentioned before, after class they have 3 or 4 hours of dancing, for prices around 5 to 8 euros. Here you have other very nice milongas:
La Milonga: Tuesday, C/ Sandoval 16, 9.30 pm. Very nice place for dancing. Restaurant Anthonys Place. Protected content
Milonga Barrio de Tango: Saturday, begins midnight and takes places in a very nice hall in a hostel. C/ Relatores Protected content . Protected content
Milonga El Tropezón: Wednedsdays and Sundays 9pm, C/ Carretas Protected content (Sol). Very nice hall, good prices for cañas and tapas. Protected content
Milonga El Templete: Sunday (my favorite!), it's in Parque del Retiro, begins 7pm til 10pm. Here's the site: Protected content Inside the park, the templete is in the northern section, here: Protected content