If this is your first Queen's Day in the Netherlands, then you are in for a treat. Or a surprise. Or a shock. Depends on your outlook on life. The main thing is wear orange tomorrow (admittedly not the top colour in most people's wardrobe) - that includes socks, hats and t-shirts. If you don't happen to have an orange hat lying around at home (really? you don't?) then not to worry - you will by the time you get back from your celebrations tomorrow evening.
Celebrating Queen's Day is a strange thing to the non-Dutchies among us. It means selling your junk on a blanket on the street, usually in the rain. For the mega-dedicated this means claiming your pitch at a truly ungodly hour and sitting tight until the rest of the Netherlands wakes up and dutifully traipses by to buy your unwanted crap. Of course, if you are repatriating in the coming months, this may be a good opportunity to get rid of the stuff you don't want shipped back.... but don't expect to retire on the takings... the Dutch are not known for just giving away their money.
Queen's Day may also mean music, beer and dancing if you head over to Amsterdam, or visit The Hague "the night before". Other cities also put on a bit of a performance, and the aim really is to have a good time and a bit of a party to celebrate the Queen's Birthday.
Although, technically speaking, April 30th is not actually the Queen's Birthday. It is the Queen Mother's birthday. Queen Beatrix celebrates her birthday in January.... no, it's not one of those weird English queen things where she has two birthdays, it's just that the weather in January is most definitely not conducive to an outside party. So Beatrix kept Queen's Day as it was when she took the throne and there is a little less chance of it raining on your blanket full of junk.....
Enjoy Queen's Day and whatever you do, wherever you go, whatever you wear - MAKE IT ORANGE!