On Friday, August 21, the annual Oak Bluffs fireworks will explode over Ocean Park at dark, following a performance by the Vineyard Haven Band at 8 pm. Bring friends, family, and a blanket or chair — and watch the sky light up. The sensational pyrotechnic display will mark the 40th anniversary of the show, which is sponsored by the Oak Bluffs association and hosted by the Oak Bluffs Firemen’s Civic Association. Make a night of it, and explore downtown after the show for ice cream and drinks, but beware, lines will be long. Rain date for the fireworks is Aug. 22, and admission is free. For additional information, contact the Oak Bluffs Fire Department at 508-693-0110.