We had a Harry Potter party for my seven year old daughter. We sent out Harry Potter post cards telling everyone they were invited to a magical celebration at Hogwarts Party Center. RSVP by owl please or if you must muggle phone calls can be accepted. We set up a table that we put all the cauldrons on. When the children started to arrive we had them decorate their cauldrons until the other children arrived. They used Harry Potter stickers and a name tag.  Once all of the children were there her older brother led them to a brick wall on our house and tapped it with his wand so that they could go to Diagon Alley. We went to the back yard and there they went to Ollivander's wand shop and got wands. (I used scewers with the sharp end cut off)  They picked up a wand and pointed it at her older brother and said the name of an animal. If it was the right wand a loud sound went off and confetti fell and he turned into that animal. The kids loved this and there were lots of unique animals and giggles. I used party poppers behind them to make the noise and once the popper went off my son knew to "become that animal." The inchworm was the silliest request. They then went to find all of their school supplies...a garden shovel for Herbology, 10 anti dementor stars, a dragon egg (these were hard boiled eggs dyed green), a pair of dragon hyde gloves (these were a pair of green gardening gloves in kids size). Once they found all that they came back and went to Zonkos and got a chocolate frog reward. (I made these with a chocolate mold). While they were eating their frogs, my son pretended to get an owl from the Magical Menagerie. It said that a crate of fizzing freezing clams got loose and could all wizards please go help. We hid about 150 frozen plastic sea shell ice cubes in the front yard. Once the kids started to pick them up, I said just be sure not to pick up any cold ones because they are poisonous. They all dropped them immediately and just looked at me. They ran and got their dragon hyde gloves so they could continue to safely pick them up. (great imaginations at this age!). After all the clams were found, they were rewarded with a magical pet. I bought a bunch of stuffed cats, owls, frogs. (These were on clearance after graduation for 75% 0ff. I just gently removed the graduation hats) I put them in paper bags and they counted their clams. They got to pick paper bags in order by who had the most clams. They loved their pets. It was a hot day so we had some popsicles and then went to Hogwarts. I had a bucket labeled floo powder. I told them we were going to see just how good of wizards they were. If they knew how to use floo powder they would automatically run to a certain part of the yard. They all of course were great wizards and reached into the bucket (of flour) and threw a hand full of powder in the air and yelled hogwarts and ran to that part of the yard. They got sorted and each got a tattoo according to what house they were sorted into.  Then we found a note from the Herbology teacher , Professor Sprout that she needed help de-gnoming the gardens. I put a hula hoop in the yard and they took turns throwing doll bodies to see who could get the closest to the hula hoop. For their reward they got a magic bean seed. We used their shovels they got in diagon alley and planted the bean seeds. We then played Whomping Willow Tag. The big tree in our yard was base and they just played tag for a while so I could set up potions class. In potions class we did the warm milk experiment. (we called the milk unicorn water) This is really easy you just take a glass of warm milk and divide it into shallow bowls. Let them choose two colors of food coloring. You put a couple drops of each color into the bowl on opposite sides (don't mix it together). Then add a smidge of dishwashing liquid. (you can be creative with what you call this ours was gold so of course it was centaur drool) The colors will start to magically "dance" around the milk. We then did the ever popular truth potion. I ground up red cabbage and vinegar in the blender (troll blood) and they each got a cup of stinky liquid. I then used a broccoli stem and shredded it in their calling it devils snare. We had two bottles of ground unicorn horn (one was powdered sugar the other baking soda). My husband and I took turns dumping it into their troll blood (we switched bottles so we didnt always  have the one that worked). The baking soda makes the mixture turn blue and bubble all over. This is always a hit and easiest to do outside on the ground as it can be messy. One little boy insisted the potion was incorrect so we gave him some of the baking soda the second time just to make it work. They were giggling and wondering who liked who and what the secrets were. We then went to the Leaky Cauldron. We had snitch cupcakes. (These are so easy. They are yellow icing cupcakes with paper wings. We had them in Harry Potter cupcake papers but it isnt necessary.) We had HP table cloths and the whole back porch decorated in all the HP decorations we have for my sons bedroom. We put up a big sign that said Welcome to the Leaky Cauldron and set up wizard chess on one table. They made pretzel wands according to their house colors. These are so easy. Just get pretzel wands and dip them in a vanilla icing container. Put the appropriate color sprinkles on them. (red for gryffindor, blue for ravenclaw, yellow for hufflepuff, or green for slytherin) They also had ice cream and other snacks. Our dog had a sign on her room that said Beware sister of Fluffy. My daughter opened her presents. We then went back outside and played "busties" with the dragon eggs they got at Diagon Alley. They each held their egg up and hit the other persons egg and the one that doesnt crack is the winner. You can use your egg until both ends cracked. Their will only be one winner. This was simple game and they loved it. Everyone got a popper to use. Just make sure you give them the rules on how they work (not to point it at anyone and which end to point away from themselves when they pull the string etc.)  We made sure all of their goodies were together in their cauldron...their wands, shovels, bean plant, gloves, pet, ten stars and their clams. A howler was then delivered. I made it out of a big red piece of poster board. You just fold it in half and address it. I folded it so it opened in the middle and glued in teeth from white paper and had a red ribbon coming out as the tongue (if you watch the movie you will get a better idea) The kids knew what it was immediately. They played pass the howler. When the music stopped they had to look into the howler and it screamed at them if they had it. My son had a mega phone and yelled their name and things like you lost how dare you loose. This is so embarrassing etc.....get up and leave the game immediately. The kids didn't want to quit playing this game they loved the things the howler was saying and it took them a couple of rounds before they figured out where the voice was coming from. Even when they knew it was my son they didn't care and still loved the game. As one last treat when they left I gave them a chocolate bug to take home. I bought these at a chocolate store but they would be easy to make if you have the time. Just wrap a chocolate bar or wafer in foil, glue on some google eyes and glue it onto a piece of black poster board cut out with legs sticking out. (I might do this for Halloween) I had lots of parents tell me the kids were so excited on the way home and it really was an inexpensive party. I got the stuff on sale because it was the end of summer sale and just used creativity on how to use it. We are sending out scrolls to say thanks and congratulating them on being great wizards. The party was 3 hours long and we had no lulls or down time so it was perfect timing. There were approximately 10 kids attending.