For my son's third birthday he was adamant on a Harry Potter theme. I searched the internet and party stores for ideas, but couldn't find any decorations that I liked so I decided to design my own. First I wanted to make it look like Hogwarts so I hung a sign outside the door that read "platform 9 3/4". I went to a carpet store and got two long cardboard carpet tubes. I stamped a stone effect with a sponge and black and gray paint. I framed the dining room entrance with them(my dining room and living room are adjacent. Then using purple, red, yellow, and black plastic material that I purchased at a party store(about 15 yards for $10), I swagged it across the windows, on the ceiling across the dining room pillars, and sliding glass doors in my home. Then I strung icicle lights on the ceiling of the living room and and randomly hung cardboard stars spray painted  with aluminum. It made a very ethereal effect. In the living room I set up small tables covered with star fabric with activities that the kids could do for each class, Herbology, Potions, and Devinations. I got the ideas from the web site here. In the dining room I decorated with ballons and streamers and covered the table with purple fabric and star confetti. I made a yellow castle cake and served Fizzing Whizzbies Punch(koolaid and sprite or ginger ale) with green and orange sherbert balls. Then I took a pumpernickel bread bowl "cauldron" and put hamburger cheese rotel dip in it with a pretzel stick for stirring, and I made a spider shaped bread bowl with vegetable dip and veggies. I also made star and moon tortilla chips by cutting out tortillas with cookie cutters sprinkling with cinnamon/sugar and baking them in the oven at 350 for about 7 min until crispy. For invitations, I tore the edges of a piece of paper and then crumpled it up in a ball then I flattened it out again, lay it out on a cookie sheet and pour about 1/2 cup cold coffee over it let it sit for about 2-3 min, drain coffee and blow dry on the tray until dry. Then I wrote letters to each child inviting them to visit Hogwarts for a celebration and rolled them up into scrolls. For each child I made capes, hats and wands. I also ordered the Harry Potter sorting hat and recorded a friend speaking like the hat calling out Houses etc. For the older kids I ordered a card game called Frog Juice where the kids get to make their own potions using some cool magical ingredients(my 7yo loved it!). While they were doing that the younger kids got to play quiditch. I ran string across my patio ceiling and placed hoops randomly around the room then I gave each little one a ballon and they tried to hit them into the hoops. They had a blast. Then for a final activity I hid keys around the yard with clues attached and they had to find the dragon(pinata) and then they got break it open(little kids hit first) and get gold coins, and candy.  In their goody bags which I made out of fabric squares and tied with gold cord, I gave them a dragon egg full of green slime, spider rings, a lightning bolt tattoo, and their hats, capes, wands, coins and candy. Everyone had a great time!