Writer-actor-Newton-ite B. J. Novak was spotted around the Back Bay over the weekend. . . . “Shaun of the Dead’’ and “The World’s End’’ star Nick Frost reported on Twitter that he was at the Brattle Theatre on Sunday to watch “Raiders of the Lost Ark.’’ . . . Bill Cosby repped his alma mater UMass during his weekend of shows at the Wilbur Theatre. . . . American League Manager of the Year Terry Francona dined at Red Lantern on Friday night. . . . Bruin Matt Bartkowski hung with his trainer at Emerald Lounge at the Revere Hotel on Friday night. Celtic Rajon Rondo was there separately.