Pen, Paint, and Pretzels, the umbrella organization for student-run performing arts groups at Tufts University, presents the third and final performance of  “Noises Off,” its spring semester Main Stage show. A raucous and hilarious 1982 farce by the English playwright Michael Frayn, the Tufts production is directed by Ana Muniz Rodriguez and Juliet Baker. Free general admission; no tickets required.