Koninginnedag or Queen's Day is the celebration of the Dutch queen’s birthday on the 30th of April. It is celebrated in different ways but the most popular one is the “vrijmarkt” (in Dutch free market). Everyone is allowed to come and set up his/her little shop. Most goods are offered at symbolic price as the primal meaning of this market is to have a good time. If you come, do not forget to barter. It is not only allowed, it is expected.
As a way to express patriotism, everyone is dressed in orange. Orange is the colour of Dutch Royal Family. The Netherlands is currently ruled by the House of Oranje-Nassau. Its members are the descendants of Willem van Oranje (William of Orange) or Willem de Zwijger (William the Silent). William I, Prince of Orange (1533-1584), as he is officially known, was the leader of Dutch rebellion against Spanish occupation.