For my son's 7th birthday we had a Harry Potter Party, 20 kids were invited. The invitations I did myself by downloading Harry Potter clipart from the internet. I worded the invitation as closely as I could to the letter that Harry received from Hogwarts.  At the top of the invitation was the Hogwarts crest and I used green lettering and a funky font. I asked that the recipients reply by owl or muggle phone which two replied by owl!  I put the invitation into an envelope and I got wax and a seal (the letter H) from the craft store and sealed all envelopes with wax.  Then my son took the invitations to school and delivered them by owl (stuffed Hedwig we found in a store). The kids went nuts for this and it was only the invitation!  All invitations and envelopes were addressed individually. I went to the dollar store and found black shower curtains, cut them and sewed them into capes for all the kids.  I then used poster board and made it into the shape of a cone and covered it with black material to make the students wizard hats. Using the clipart I printed off the Hogwarts crest, laminated it and then hot glued it onto the front of the hats so they looked official.  I then used thick elastic and hot glued it onto both sides of the hat in order for the hat to stay on their heads. Once the kids arrived they were sorted into their houses, I had downloaded, printed and laminated house badges for all the kids so we knew who was in what house.  For the sorting hat we used a black witches hat and placed a baby monitor up inside it and had someone in another room calling out the house names.  As each child was sorted they came and received their cape with badge attached and their hat.  I also painted scars on all there forheads if they wanted it, which of course they all did. Once the kids were sorted we then divided them into 2 groups and they were sent off to classes. There were four classes, Potions, Spells, Herbology and Transfiguration.   For Potions I had two activities planned, the first I had taken baby food jars and covered them with black material to resemble cauldrons (the party was in July so there were no halloween props available)and we used vinegar and baking soda to bubble up out of the cauldrons, then I put food colouring in them and they did it again.  They each had turns doing this many times. Once they were done we cleared that away and they made "Potions" which was actually vanilla and chocolate pudding along with coloured sprinkles, marshmallows, chocolate chips etc and they layered them into see through plastic cups and stuck popsicle sticks in them at the end and they were thrown into the freezer and the child got to take it home with them. Next class was Tranfiguration and for that they had to make a pair of Harry Potter glasses out of black pipe cleaners which I had already precut and a pair made to show them what it would look like, once the glasses were made and put on, voila they had transformed into Harry. Next they went to Herbology where they painted clay pots and planted seeds in them once they were finished drying. On to Spells class, this is where they received their wands (wooden dowels bought at the hardware store and cut down to size) which they painted, glittered, feathered, whatever their little hearts desired.  Once all the classes were finished each child got a LARGE gold loot bag to house all there goodies.  Inside the loot bags I had made full page booklets of Harry Potter puzzles, mazes, word searches, colouring pages, you name it.  To go along with their books I made pencil broom sticks using yellow HB pencils and raffia tied around the end of it to look like a corn broom, I wrote Nimbus 2000 on them with black marker.  I also downloaded, printed and laminated Harry Potter book marks. I had a recipe for homemade playdough so I made it in all the house colours, made little balls of the dough and then put one of each colour in a ziploc bag to put into their loot bags. In each loot bag I personalized a certificate with each childs name stating they were an official wizard after finishing their day at Hogwarts. Once the classes were over we all went outside for the pinata which was a wizards hat I ordered online. We also played a game of wizard stomp which consisted of having balloons tied around the ankles of the kids and each child had to try and break the others balloon while tyring to protect their own a prize was given to the last child left with a balloon.  After this we ate lunch which was pizza, chips, pretzels, cheezes and a punch made up in a big cauldron.  I bought gold and silver plates, napkins, silverware and I found plastic goblets at a party store for each child to drink out of.  They took these home with them.  The cake was of course Harry Potter done at the local grocery store with Harry playing quiddich. Once lunch was done we opened presents and the final stop of the day was at Gringotts bank where each kid got a small cloth bag (I found cool material and sewed them) filled with money (plastic money found at dollar store).  After they got their bag of money they were allowed one at a time to go to Honeyduke's Candy Store and purchase candy and Harry Potter stuff. I had made one of the bedrooms into the candy store and set up a table of goodies.  I had found at a party store Harry Potter things such as a nimbus 2000 key chains, spell books, stickers, cups which I filled with gummy worms and wrapped in cello etc.  I also made candy for the kids such as chocolate covered licorice (wands), chocolate covered frogs (gummy frogs I covered in chocolate), Harry Potter chocolate on a stick (made with Wilton's candy molds), store bought pop rocks, bertie botts beans (jelly beans inside cloth bags I had made) and the list goes on. Out in the front yard I had used huge boxes (appliance boxes) and I had someone draw a train (Hogwarts Express) on it and I painted the whole thing, it was big enough the kids we able to get in it. The front door was covered in brick (red bristol board we drew bricks on) and a sign above it saying Platform 9&3/4. The kids had to enter through this door of course. All the decorations were in the house colours, red, green, blue and yellow, streamers and balloons everywhere! I had painted styrofoam balls gold and stuffed feathers in them and hung them around the house for golden snitches. This party took months to plan and many friends to help out the day of, but the kids had the best time.  And truth be told so did I.