The large lecture hall was remodeled during the Chamberlin Hall work, to allow for more electronics and for a lecture demonstration prep room in back. The old hall (it is underground) leaked a bit, so the powers-that-be took this opportunity to reseal the courtyard above it. For a couple of weeks workers stripped out the old loose sealant in the cracks, cleaned and ground out the cracks, and filled them with brand new goo.
Apparently they also flushed out the accumulated silt that slowed water flow, because the new hall leaks worse than before, and the prep room has a substantial puddle in the middle of the floor. Dedication is coming up soon . . .