Pandora's Garden, the sign says, the name chosen in a student competition. What it is, is a garden tended by the principal and some volunteers, with boxes specified for the various teachers--they are expected to come up to the roof periodically to harvest
The occasion for the samgyupsal party was unrelated to my re-contracting interview. It mostly had to do with yesterday being a really nice string day, and the planting boxes starting to bear. The samgyupsal was cooked in regular frying pans instead of griddles that can drain off the oil, so those who cooked needed to soak up grease with paper towels.
Here's a pic of the scene on the rooftop at Yangmyung Cho. That's the VP poking her face in at right.