Gothamist's recap of last night's Gossip Girl is about how all the scenes from this week's episode were shot in Brooklyn Heights:
Gothamist: Gossip Girl's Field Trip to Brooklyn Heights: While last week was definitely Long Island City week on Gossip Girl, this week's version of the "exclusive" Upper East Side dropped squarely in Brooklyn Heights. The opening scene, featuring some sort of perverted choir singing Fergie's "Glamorous," was shot on location at Packer Collegiate Institute's 3rd floor chapel. The gang revisited Packer later on at the contrived 'Ivy' reception, which went down in the school's backyard garden. From there, the gang didn't have to travel too far for their extracurriculars. The fantastic field hockey practice/Serena-Blair catfight took place only a few blocks away from the school at the base of the Brooklyn Bridge in Cadman Plaza Park.