This party was for my soon-to-be 7 year old son, who badly wanted a Harry Potter home party. We studied the ideas listed here and mixed and matched what we felt was the best. It turned out to be a huge,fun, success! This party lasted 3 1/2 hours easily without any need to look for something to do. In fact, we had to cut some things out!  The ages were 5-10.  We created the invitation on the computer and then printed it out on parchment looking paper.  The invitation went like this:                    Hogwarts School of Witchcraft and Wizardry Headmaster: Albus Dumbledore (Order of Merlin, First Class, Grand Sorcl, Chf. Warlock, Supreme Mugwamp, International Confed. of Wizards) Dear       ,      We are pleased to inform you that you have been accepted at Hogwarts School of Witchcraft and Wizardry. You'll receive a list of all necessary books and equipments upon arrival at Hogwarts. Our first celebration in the great hall for "     " 7 year old birthday.    Tern begins on "party date". We await your owl (RSVP) no later then "RSVP DATE".  Please report to platform 9 3/4 (our porch) no later then 2:00 pm sharp.  Your parents can pick you up at 4:30 at platform 9 3/4.     Yours Truly    Professor McGonagall     Deputy Headmistress     Phone# & Address  We sealed the envelope with purple was (melted crayon) and delivered them to each child. We were surprised how they instantly believed they were accepted to hogwarts, even the ten year olds! Our party ended up pretty big, 17 children including the birthday boy. We used our living room, family room, kitchen, deck, back yard, small shed & the garage to create this party.  This all might be long but it was so much fun to pull off. We made signs for our front porch. One said platform 10, one said platform 9. We hung streamers down from the roof so that the "students" would walk through them.  Our Uncle Len, who is 6'5 dressed up as best as he could as Hagrid and welcomed all the kids to the part. I had two ten year olds attend this party. They were announced to everyone as the "Prefects" and everyone should listen to them. (They were my helpers).    All the adults were dressed up as a witch or character of the party. I was professor McGonagall, my brother was Hagrid and later Voldermort, and the rest were dressed as witches. Presents were taken by a witch to the great hall.  Children were first directed to a jar filled with Bernie Bots Jelly Beans and were told to guess how many there were and to put it in the special raffle box.  (I bought different flavored jelly beans from a special candy store in the mall. Much cheaper then buying the real Bernie Bots Jelly Beans.)  They were then directed to the Living Room and given a lunch bag. At the coffee table we had an assortment of Harry Potter rubber stamps and markers and they were instructed to decorate their bags.    Once everyone had their bags decorated and had arrived, we went over the rules at "Hogwarts". No one was allowed upstairs, and no one was allowed in the basement where Fluffy was located.  (It worked out that our three dogs were down in the basement and every now and then they would bark to make it seem real!)  We also warned them that the Sorcerer Stone had been found to be missing and that they should keep an eye out for it!  The first stop was gringotts bank!  We led them out onto the porch.  We have an octagon attached to the deck so we had all 17 children circle the octagon while I explained the game. We were going to blind fold each child one at a time. Then we dropped a baggie filled with money on the deck. We spun them around and then the kids tried to help the student find his money.  The money was made out of different washers and bolts that I spray painted gold, copper and silver.    After each student found their money, we took them back into the house to Diagon Alley (our family room).  Here the students needed to by their supplies.  In each of their lunch bags was a list of what they needed. A wand, a cloak, and a hat.  Each item cost a specific amount and the kids had to buy their supplies. My brother, Hagrid, was sitting with a Cauldron filled with wands (different sized sticks and dowels spray painted different colors of brown) and in charge of making sure that each kid had his very own personal wand. On his T.V. tray was a stack of cans that the children were supposed to point the wand at and see if it would destroy the cans or not.  Using his knees, he would shake the table and make the cans fall down if the wand wasn't meant for that child.  The kids walked away feeling like that wand was just for them!  My mother, a witch, was in charge of measuring each child for their cloak.  We cut simple black material out and tied it around their necks. They went to my sister ' n law next who was in charge of selling them their Harry Potter Party hats.  Once they were done shopping, we led them to the living room to be sorted into their respective houses. Since we had SO many kids, we were able to sort them equally into the four different houses.  We had purchased Letters Representing the four houses at a material store and made them different colors.  They were just like stickers and we were able to place them on each cloak easily.  We had splurged and boat a Sorting had and had him sitting on a TV Stand with a baby monitor taped far up inside of it.  My husband was upstairs hiding with a list I had made of each kid.  We had a special chair set up so that each kid could sit on it. I had a list that matched my husbands. I stood near the stairs so he could hear me call off each students name. It was so much fun!  I personalized the list to say something about each child that was personal.  For example...1.) Adam...Ahh yes.  The son of a police officer hey?  Big Brother to.  Makes you pretty smart. A bit witty to I would say...RAVEN CLAW!  I tried to use the description of the different houses and blend them in with the description of the kids.  It was hysterical to watch their reactions! Of course the Birthday boy went into Gryffindor! My husband used a raspy voice and made it sound so good.  After they were all sorted we took them outside for a group picture that I enclosed into the Thank You cards. My brother took the monitor out right away when no one was looking, luckily, because some members of Slytherin tried looking in the hat to find the monitor and were dumbfounded when it wasn't there! After pictures we went to the kitchen for potions class. Each child received a mini-culdron and stood around the table. We attempted two potions.  We had test tubes that a dear friend let us borrow and clear plastic cups.  Potion #1    Need Clear Plastic Cup    You need 1/16 of a cup of Dragons Sweat (lemon Juice)            Trolls Blood (Juice from a purple cabbage)   Blend the trolls blood with Dragons Sweat and watch it turn pink!            Mix 1/4 teas ground unicorn horn, turns purple(Baking Soda)            Mix 1/8 cup of Poison (vinegar) and watch it turn pink again.            Mix 1/4 teas of unicorn horn again and watch it fizzle & hopefully bubble over!  Potion #2      Use your Harry Potter Cauldrons        Fill ahead of time with Cornstarch mixed with Glitter       Mix some swamp water (water with green food coloring)        Stir with a plastic knife.  It SHOULD become thick. When you pick it up it becomes liquid again. (Cover with plastic wrap so they can take home.)       We were going to have a Moaning Myrtle Game, but it became really Hot on the Deck and we were starting to loose time. The game would of been having everyone sit down with one person in the middle blindfolded.  Have a prefect point to a kid and he either has to moan or cry and the blindfolded kid has to guess who it is.      We next sorted the four houses up in the black yard, provided them with a broom and had a race in our back yard. They had to cross the bridge that went over a pond, run around the "womping Willow tree" completely, run around Hagrids Hut (our small shed) before getting back to their team. It was hysterical to watch them try and do this without dropping their brooms or running into each other. When the race was over we attempted a Quidditch Race.  Each team was given a spoon to hold.  Each one was given a painted snitch (below) to hold in the spoon. They had to do the race again, this time without dropping their snitches! Tired out we went on to the final stage. The Great Hall was in the garage.  We had a ramp that they had to go down because at the time our house needed to be wheel chair accessable.  We had the soundtrack from Harry Potter playing.  Streamers and balloons and snitches (styrofoam balls painted gold with feathers stuck into them) were hanging or floating everywhere giving it a very magical feel. We used two tables making a very long table for everyone to sit around.We had Cake & Cupcakes (that had pop rocks sprinkled on it.)  We then had cool aid for the kids and put pop rocks into the drinks to make them fizzle.  WE then did singing and presents. The witches were inside the house filling their bags with favors and treats. Finally we went out to Hagrids Hut and found a pinata of Norbert.  While they were attacking the pinata, Hagrid went upstairs and changed into Voldermort.  Everyone at this point was so wrapped up in the pinata that they didn't see him come up in his hooded cape with skelatol mask on.  He stood outside looking in at them until one girl saw him and screamed. Half the kids fell screaming while the rest ran out and started chasing him.  He magically disappeared and turned back into Hagrid leaving a lot of the kids dumbfounded yet again!  At this point parents were slowly coming to get the kids.  It was a very busy magical time and I loved hearing the stories of how believable it was and how it was the best party ever!  Hope this gives you all some ideas.