There'll be a fashion contest for the best-dressed wizards and witches. You can also take part in a Harry Potter Quiz, or a Hogwarts Twister Game and get the chance to poke nasty Aunt Petunia in her bum to deflate her. We'll have a fortune-teller with a crystal ball for those who want to know what the future has in store for them. She can answer all your personal questions but unfortunately she won't be divulging any secrets about the new Harry Potter book! We'll also be providing magical potions, antidotes and snacks to sustain you while you wait for the clock to strike one.Similar craziness will be going on all over the globe, of course.
What I'll be interested in here in Amsterdam is how many non-native English speakers will turn up. The Dutch translation won't come out until November, when there will be more celebrations (though under colder conditions). I figure there will be a fair number of expat kids of around my daughters' age, but Dutch kids don't start studying English until they're around 10 and won't be capable of reading a Harry Potter book in the original until they're a few years older than that. So how many Dutch teens will be uncool enough to show the enthusiasm necessary to show up at the party? The books are popular with adults, too, of course, and I imagine most adult Dutch fans read them in English. I wouldn't think many grown-ups would come to the party without accompanying children, though.
We've got the Dutch translations of a couple of the earlier books, and I'm surprised at how many changes have been made to the names of places and characters. Apparently, the German translations keep the English names, which is a turnabout from television: Dutch TV subtitles foreign programs and movies, while the Germans dub (Damn them! It stops me from making use of the umpteen German channels we can receive.).
F'rinstance, Hermione is Hermelien, Quidditch is Zwerkbal, the Malfoy family is named Malfidus (Latinized rather than Frenchified as in the English version, I guess), Harry's awful cousin Dudley Dursley is Dirk Duffeling, and so on. I especially like the Dutch name of the Diviniation teacher, the hopeless fraud Sybill Trelawney. The Dutch translator retains the meaningful "Sybill," but he surname is Zwamdrift, which I think literally means "Drivel passion." Hogwarts School of Witchcraft and Wizardy gets an improvement as well: Zweinstein Hogeschool voor Hekserij en Hocus Pocus. Dumbledore is Perkamentus ("parchment," but Latinized). But Harry Potter is still Harry Potter, and Voldemort is still Voldemort (or Hij die niet genoemd mag worden if you're afraid to say his name).
There's a website that will tell you what terms are used in various languages for Potter-talk.
Of course, none of this is as silly as the "translations" sold in the U.S., where the language has been Americanized.