It's a springtime ritual on the Vineyard, a celebration of the end of winter combined with the perfectly-timed opening of Dairy Queen on a half day of school. As the early closing bell rings, hundreds of students make a beeline for the ice cream shop, some making their way on foot from the nearby Edgartown School, others winding their way from locations throughout the Island, ready to celebrate the start of spring with a frosty treat in hand.