Since I am a big Harry Potter fan myself, I probably got a little bit carried away, but planning this party was a lot of fun... my two main goals were to plan fun activites for the kids and to make everything as low cost as possible.  Invitations:  I sent every party guest a letter from Hogwarts inviting them for special midterm classes. I modeled it after the letter sent to Harry in the first book and from another invitation submitted on the website. I addressed the letters to Miss Jane Smith, stating Hogwarts was holding sepecial midterm classes in Transfiguration, Care of Magical Creatures, Charms, Astronomy, Divination, and Potions. I also asked each guest to bring a muggle broom for a game in Quidditch, weather permitting.  I also said we would be having a banguet at the end of classes to celebrate my daughter's birthday. I used parchment paper and matching envelopes I purchased from Kinko's so I didn't have to buy a huge set and I bought stickers from ebay that had the Hogwart's emblem on them. I printed everything on my computer with green ink.  I then made some owls... I purchased all the supplies at Walmart. I used a foamie sheet... cut out 3-4 size egg shapes plastic eyes and a small triangular beak and semi circle feet made from orange construction paper that I had on hand.  I then hot glued a magnetic strip to a clothes pin and hot glued the owl to the other side. We put the letters in the owl clip and stuck them to each invitee's door. I really don't think I spent more than $10 and they turned out really cute. Party Supplies:  In the letter I stated Hogwart's would be deguised as a muggle home so I didn't have to do much there.  I did buy some silver platters plastic goblets and gold and maroon candles from the dollar store.  I made wands for all of the guests... I bought precut wooden dowel rods from the craft store... I made them all look different.  I used some craft paint that I had on hand ... I drew some designs using a sharpie mixed glitter with some... then after they dried I used a paint pen and drew Ollivander's on the bottom/side to make them look official.  I also transformed my side board cabinet... one side had a Honeyduke's Sweet Shop Sign and the other side had a Potions sign with a skull and cross bones both made on my computer. The Honeyduke's side was filled with candies all labled... I bought a few Harry Potter candies but made most of my own due to the cost.  I bought some chocolate frog molds on ebay and a Harry Potter chocolate pop mold that had rat owl glasses and a witch hat on it. I just melted some premade chocoate candy drops poured them into the molds... mixed some rice crispies into some and I also made edible wands... I dipped large pretzel rods into the melted chocolate.  I sewed some fabric bags out of material I had on hand and filled them with gum balls and labled as drubles blowing gum. I also bought some pop rocks and labeled them as Weasley whizzies.  I bought some fruit gummie packs that were shapped into long strings and labled them as inguana intestines. I decorated the inside of the cabinet with different curly ribbons to make it more festive.  The potions cabinet had all of the potions ingredients labeled.  I followed a recipie from another entry and added a few of my own.  The cabinet was full of cobwebs and a spider ... I used old bottles on hand and used crumpled brown paper bags for other ingredints.  I bought plastic black couldrons for all the guests... used a paint pen and drew their names on each.  My daughter wanted the $40 quidditch cake from the store... so I bought the cake topper for $7 and made the cake myself.  We also bought a bunch of snack food that could all be baked in the oven small hot dogs egg rolls pizza bites and tacos and I premade a platter full of baby carrots black olives tomatoes and grapes.  When the guests arrived they were sorted into 2 houses - Griffindor or Ravenclaw.  I put the house stickers in a witch hat and they each picked one out.  Then they chose wands.  I had the wands in a cup that had a button on the bottom... when the button was pressed the cup would illuminate.  So I held the cup I told each girl to select a wand tap the side of the cup and say 'lumos'... if the cup lit up that was their wand if it didn't they needed to chose another wand.  Once their wand was chosen I had them say 'nox' to extinguish the light.  I then told all the girls to get their cauldrons and to keep them with them because they would be awarded with gold galleons (plastic gold coins) based on their performance in each class.  They could then spend their money at Honeyduke's at the end of classes.  First we had our transfiguration classes. I printed pictures off of DLTK-Kids.com ... an owl mermaid phoenix unicorn etc... all magical creatures.  As they colored them I had each girl try a few berttie bots... they got a cold coin for each one they guessed correctly ( a lot of laughs there). Then I explained they were going to try to transform into their animal but things went horrible wrong and they all got mixed up. I mixed up the animals and pinned them to the girls backs... they had to ask me yes or no questions to figure out who there were like " Do I have 4 legs" or "do I have wings etc... they got a gold coin once they guessed correctly. Then we had care of magical creatures. I told them that baby animals were lost outside and needed to be rescued.  I had hidden unicorns, owls, and a pegasus outside before everyone arrived.  I described what some of them looked like and told them they would receive a galleon once they found one. I also told them they could only find one, but there were two bonus items... Harry Potter's glasses and Scabbers the rat that they could also find.  Then we played Quidditch... this was so much fun. The girls divided into their teams.  They each had their broom in between their legs. I had two basket ball hoops at each end of the yard (the plastic ones).  There was one basketball that they used as the quaffle to make baskets, and 2 soft balls that I used as bludgers to throw at the girls... if I hit them, they would have to sit down for 9 seconds before they could resume play.  As they ran back in forth with the balls, they would try to make baskets... everyone was laughing... it was hilarious! It really was challenging... holding a broom and a ball while trying to make baskets. After I thought we had enough, I threw out the snitch, a styrofoam ball painted with gold glitter and yellow contructions wings. Then the game was over.  The winning team each got a galleon and the person who found the snitch got an extra galleon.  Then we went inside for charms. I bought a bag of magic tricks meant for party favors ... no more that $2. I used the cup and ball trick... I demonstrated... we used the words... 'appearo' to make the ball appear and then 'evanesco' to make it vanish. I also used the chinese finger holders... we told them it was devil's snare ... they had to relax to let their fingers out.  They all had fun learning their tricks. Then we went to the astronomy tower.  I made some constellations out of white paper, and glow in the dark paint ($2-3).  I just made dots to form the big dipper and the little dipper.... and a few other constellations... I showed them what they would look like before we went to the 'tower'(basement).  I then told them they had to figure out which one I had made up. I made one look like the letter H... since my daughter's name starts with an H.  I also turned on a sound machine that played a summer's night so the girls could hear crickets while they studied the constellations.  I told them they had to keep it to themselves... and write it down on a peice of paper .  Whoever got it right, got a galleon.  I also told them to write a question down on the other side of the paper that required a yes or no answer. Then I stuck them in a cup for later.  Then it was time for potions.  I showed everyone the potion's cabinet... lots of oohs and aahs. I had written up the ingredients on an eraser board and had it out for everyone to veiw. I pulled out some plastic black bowls I got for 10 cents each and some measuring cups and tweezers and handed them out.  I let each girl pull out an ingredient and we passed each around and added them to our bowls.  I told them they were making poly juice potions for the ministry of magic to use for a later date. We used red cranberry juice, laundry detergent, vinegar, baking soda, flour, pop rocks, gummy witch fingers, flies, fangs and brains (I gave them all potion names from the book). I would tell them to stir clockwise then counter clockwise... we stirred with pretzel sticks. As we were making our potions... I put everything into the oven as we were stirring.  Then I gave everyone a galleon.  I then told everyone we could go to honey duke's once the table was cleared.  As you can imagine, it was cleared in no time.  I covered the table with a table cloth. Then they each took a turn at the honely duke's cabinet. I told them they could each spend 8 galleons... 1 galleon per candy... if they had extras they could go back after everyone had a turn so they each got a variety of candy. As they shopped... I got the table set with platters full of food, candles, purple plates, and goblets full of sprakling juice. They had a blast feasting... giving a toast to my daughter.  Then we sang happy birthday and had cake... I used magic candles, of course.  Then it was present time. That's when we practiced divination... A birthday guest would get a gift and hand it to my daughter... then I would have the guest pick a question out of the cup (one they hand not written)and read it aloud ... I was holding a magic eight ball and read the answer that floated up.  They asked some cute questions... so that was fun too.    The party lasted around 3 hours.  I heard some girls say... this was the best party I have ever been to" and "I knew this was going to be fun but not THIS fun!" I have 4 kids so I hope the younger ones deside to do this as well... it was LOTS of fun for all!                "