A ridge vent assembly (10) extends along the ridge of a roof (12) of a building structure and is provided with multiple plies (30) of corrugated material (26, 110). The corrugations of the plies define small diameter passages (32) that communicate a vent opening (20) cut along the ridge of the roof with ambient atmosphere. A baffle (38, 100, 114, 138) provides a means to close the vent to prevent moisture from entering the building through the vent opening. In the preferred embodiment, the baffle terminates into one or more flexible bubbles (54, 102, 104, 118, 128, 140). When wind speed increases above a predetermined wind speed, the baffle moves into a position that seals the vent opening from external moisture. When wind speed is below the predetermined level, gravity allows the baffle to go to an open position, wherein exhaust from the building may escape from the vent opening and through the vent assembly. A similar cloth strip and bubble can be used to weatherstrip windows, doors, and other building openings by securing the movable member to the window or door frame.