Princeton University has evacuated, citing "a bomb threat to multiple unspecified campus buildings." In a 10:26am post on the school website, the Office of Communications told staffers and students not to "return to campus for any reason until advised otherwise." In follow-up Twitter posts, the school added, "This is NOT a test," but also pointed out that the campus was sparsely populated to begin with. "Regular classes are over and Commencement was last Tuesday," it wrote. "Most students left campus days or weeks ago." (More Princeton University stories.)