We had a great Harry Potter Birthday for My son Kyle.  Thank you so much for having this site.  I got many of my ideas from it. We first sent out invitations that mirrored the invitation Harry had received to Hogwarts. (Yellow parchment paper, emerald green ink , and a purple wax seal)  The kids loved them and they were very excited for the day of the party. The party took place at our house. We decorated the house With shields, banners, streamers.  Each room of the house was a place or room from the book. For example the play room was Hagrid's Hut, The garage was the Forbidden Forest, some of the bedrooms were classrooms. As the guests arrived they came to our porch which was transformed into Kings Cross Train Station. We had a hidden tape recorder playing the sounds of a train and an owl hooting.  On both sides of the doorway of the porch we had signs, one was Platform 10, the other was Platform 9.  In the doorway we put up a curtain of streamers that the guests walked through(this was the barrier that harry had to walk through). Once they passed the barrier they came to our front door which had a sign that said Platform 9 3/4. Once the guests arrived we gathered them up for their first lessons. they came into the Grand Hall.  I dressed up as Professor McGonagal, and I had several other adults dress up as other characters from the story.  We started with the sorting hat.  I had a witch hat on a bench. We used Baby monitors in the hat to make the hat speak. (YOU could use walky talkies also)  The hat said his little song and then called each guest up and told them what house they belonged too, they then were fitted with a cape, a sticker of their house they belonged to, a bag containing a wand and glasses, and a Tattoo of a lightning bolt was tattooed on their forehead.  They then sat back down until everyone had their supplies for their journey. We then had a very short History class lesson. In the book the history class was taught by a ghost who slept through his death. I had made a ghost out of a balloon and sheet in the corner. I also had him snoring. I told the kids that I would teach for the sleeping ghost. I went over some key things from the story for those guests that didn't know a lot about the book.  after that we went to Honeydukes (candy store). I had made a lot of food and candies and had the kids sample them. (ex.  Cockroach Clusters which was rice crispy treats in chocolate, Chocolate bugs, Dragon Snot which I put some wizard ice (pop rock candy)into this made it fizzle, wands, Bettie Barts Flavored Beans, and Chocolate Frogs.   The Chocolate frogs were wrapped in Cellophane and had a trading card included.  In one of the wrappers was a secret note. The person that found the note gave it to me and I read " The sorcerer stone is missing. We must find it. You will find more notes with clues on your journey. Now go to flying lessons." We then went with Madoom Hooch to flying lessons in front of our house. We had two witch brooms and had relay races. Someone came with a delivery from a toy owl. It was the next note which said "You must go to the Forbidden Room and Find the Dragon Eggs, but beware it is heavily guarded."   we then went and looked at the Maurders Map for directions and went upstairs.  Kyle's room was the forbidden room.  We had a tape recording of dogs barking.  The kids guessed it was Fluffy guarding the room . We sang Happy Birthday to Kyle to put Fluffy asleep.  I then reminded them that their was a Silly Dementor somewhere that likes to tickle people. The only way to get rid of him is with our wands. We must say "RIdiculoso" we opened the door and out came the dementor and the children got rid of him.  They then searched for dragon Eggs.  the dragon eggs where painted gold and black and contained a plastic dragon covered in homemade goo.  They hatched their eggs in Moaning Myrtles bathroom across from Kyles room. One of the eggs had their next clue. "  Find the Golden Snitch and you will Find the Sorcerer Stone. Go to Potions Class."   Off to Potions Class. That was a bedroom that looked like a dungeon.  Here we did Science Experiments.  Many of them found from the internet. this was really fun but I wont write about it because it would be very long. The last experiment we did was invisible ink. One of the papers had the next clue  "Go to the forest" we went to the forest or Garage.  We opened the door and it was dark. they took out their wands and said Luminous and the lights went on.  I had green streamers coming down from the walls stuffed animals , and in the middle of the garage was a pinata of a giant golden snitch. (Easy to Make)  We did the pinata and when the pinata broke candy and toy rubies came out.  One of the rubies said Sorcerer Stone.   We then had cake, opened presents, and played in a castle jumpy house.  when the guests left they received a report card that also was a thank you card and a book with information about the science experiments.   It was a great party and I still have parents and kids thanking me for it.