Pen, Paint, and Pretzels, the umbrella organization for student-run performing arts groups at Tufts University, presents the first of three performances 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. The show will be repeated at 8 p.m. on Saturday, April 5, and at 3 p.m. on Sunday, April 6.