Today is a particularly special Queen's Day as Queen Beatrix is abdicating to her son, Willem-Alexander, current Prince of Orange. Essentially she, as her mother and grandmother did before her, decided she's too old (she's 75) and wants to turn things over to a younger generation. Willem-Alexander will be the first king in 123 years. So next year, we will celebrate King's Day (Koningsdag) which will be on 27 April, Willem-Alexander's birthday...except next year it will be celebrated on 26 April because 27 April is a Sunday. Like I said, pratical people here in the Netherlands!
The Dutch royal family does things a bit differently. There is no "crowning" and the King won't wear a crown. The Queen will literally sign a piece of paper giving up her power and turning it over to her son. It's called an investiture (the act of establishing in office or ratifying ). Unlike the United Kingdom (okay, honestly I know next to nothing about royal monarchs so I might get some of this not-quite-right), the Dutch royal does have a role in actual governance. The Queen or King, much like the US President, signs into law what is passed by the legislature. If the Queen or King doesn't sign then it doesn't go into law; like a Presidential veto. Willem-Alexander has said that, as a Democrat, he will sign everything that is passed by the legislature. He was asked if the legislature passed a law abolishing the monarchy (this is not something that is acutally likely to happen), would he sign that. He said he would. His mother was said to read, in detail, every piece of legislation that came to her. The new King reportedly wants to get away from that and spend more time promoting the Netherlands on the world stage.
I'm going to try to get into town today to see what's going on here (which will be absolutely nothing compared to what's going on in Amsterdam). I'm one of the only people who actually has to work today and even before 0700 they were already setting up and blocking streets this morning. Since it's my last Queen/King's Day here I'd like to check it out.