This was a great one. (Almost two weeks ago, sorry.) I found the ideal way to do it: first read the play in English, then in Spanish side-by-side, then in Spanish on its own. Then watch. This is obviously very time-consuming and won't always be possible, but my comprehension (not surprisingly) goes way up.
It was Final de Partida de Samuel Beckett (Endgame). Weirdly I had never gotten to know the play til then. A great production at the Teatro San Martín, like the Lincoln Center of BA. Directed by Alfredo Alcón, the guy who played Hamm (the old one in the chair). He's apparently an icon of BsAs theatre, and it showed. The long rehearsal process showed too: an amazing level of detail and humanity in a play that I imagine could come off as pretty chilly and abstract. I just googled him, holy crap, he's 83. That's insane. You had to see his level of energy (even in a chair.) I liked his direction as well as his performance: played up the kind of vaudeville-clowniness of the Clov/Hamm pair, an element that hadn't leapt off the page when I read it. They really seemed like cousins to Didi and Gogo.
Dude who played Clov (Joaquín Furriel) was quite a bit younger than I'd have thought, could have been Hamm's grandkid. It turns out he's a telenovela guy! Because the San Martín is a state-sponsored theatre and therefore supposed to make Art that rises above commercial concerns, the presence of a telenovela actor there in Beckett was seen by many as the ugly imprint of BsAs right-of-center mayor. I couldn't fault it too much myself, seeing as Furriel did a fine job, and at Lincoln Center both would have been TV/film actors (Alan Alda and Woody Harrelson? Actually I'd see that.)
Most cooly, it was Nick's first day here! And closing night for the show, so like a trouper he read the play (in English) on the plane and saw it with me. Apparently this works well for him as a way to see theatre (he was laughing along with me at the funny bits) so I'll have company for at least some of my theatre evenings out.