EVENT: We're told the Reverend Billy and Savitri are leaving for a while, and they'd like the chance to say goodbye to the Church. To start off there will be a petition gathering and 1st Amendment singing at the NW corner, which will be followed by the Push Back Picnic near the Abraham Lincoln. They say, "there are many ways to enjoy and help us resist the theft of our parks by vulture investors. So bring some food and drink, let's remember our remarkable year - and create a blessing for the future!" 6 p.m. // Union Square // Free MUSIC: Today's interviewees , Oxford Collapse, join buzz band du jour, Frightened Rabbit , tonight at Southpaw. Catch the former before they're back at the end of the month playing much larger venues. 8 p.m. // Southpaw [125 5th Ave, Brooklyn] // $12 THEATER: Richard Nelson's 1989 comedy Some Americans Abroad skewers the backstabbing and careerism of American academia, as a group of professors lead their boorish students on an ostensibly edifying tour of England. “With a crammed itinerary and barely enough time to digest the sites, the students’ behavior devolves from appreciative to appalling while the professors confront the emptiness beyond their idealism.” The first New York production at Lincoln Center starred Bob Balaban as a sycophantic professor; this new Balabanless revival at Second Stage is currently in previews. – John Del Signore 8 p.m. // Second Stage [307 West 43rd Street] // $74 SCIENCE: ...