Blizzard Entertainment announced today that an additional 250,000 standard box copies of World of Warcraft will be available in retail stores across Europe on 15th April. This new shipment of boxes follows the sales of more than 620,000 copies in Europe since its launch on 11th February. As part of a new initiative, players will find a 10 day Guest Pass in each of these 250,000 boxes, which will allow them to invite a friend to play World of Warcraft with them on a 10 day free trial.