So I went on Saturday to check out the BWAC closing fest, and happened on the Red Hook Ballfields that I read about on this board.
Though I knew I had to save room for dinner, I could not help but purchase a pork and cheese pupusa, hot off the griddle. This was heaven -- the shredded pork and mild cheese came together in hot gooey goodness.
The folks cooking there seemed to be from El Salvador and Guatemala. The other stands looked and smelled wonderful, and included many things I did not recognize (I'm still learning). As I was leaving, I bought the incomparable mango on a stick, which the vendor doused in lemon juice and sprinkled with salt and chili pepper. I had never had mango this way, and though I couldn't stop accidentally getting the pepper in my nose, I found it messy and delicious.
I recommend this trip to Chowhounds... certainly a nice bike ride from Park Slope. I look forward to hearing other reports of the food, and plan to report back on other things that I try.