For my daughter turning 5 and my son turning 3 they wanted a Harry Potter/Wizard  party, so I watched the movies and read the books, rented a nice building  next to a local park and dressed the place up like Hogwart's School of Magic. The invitations were white paper steeped in coffee to make the paper look aged, they were  written as  an invitation to the school of Magic and Wizardry.   Upon entering the building the kids drew a piece of colored paper from a sorting hat  i made, the color of the paper  determined the house they were in, the presents went on an "owl post" table for the mail drop. There was a score  board for each house, houses   scored points for various activities, we made sure to allow each house to score the same amount of points so everybody won. Centerpieces for the dining tables were  terariums of  carnivorous plants, venus fly traps  etc., sealed jars with molding baby carrots(for goblin fingers), squares of bread(for ghoul toast), cooked spaghetti(dragon brains), peeled grapes(blind newt eyes), everything a wizard might need for casting spells, there also were lit candles floating in glass jar. The counter was set up with experiments as the potions class, each child was able to make a  mixture of monster slime to take home.  Snacks were pretzel broom sticks and wands, chocolate dipped gummy frogs, of course the all flavored jelly beans and other wizardy snacks.  I made a real wand for each child out of good sturdy sticks I found  around, stripped the bark, decorated with copper wire for dragon heart strings, fishing line for unicorn hair, red feathers for pheonix feathers and other "mystical" devices. The sticks were stained and finished so they would hopefully last and withstand lots of swishing and flicking.  Other party favors consisted of pencils decorated with rafia to resemble brooms with "Nimbus 2000" on the stem, a small book with various  good luck spells and charms, other wizardy goodies. I also hung paper candles over the eating tables to resemble the dining hall. I didn't bother with costmes as I didn't know the sizes  of all the kids and I was trying to make  the party on a small budget but I think it turned out fine all the same. The kids played games like The Golden snitch, where the won points for finding a styrofoam ball painted gold  hidden with other sized balls painted as the other quidditch balls. I think the kids had a good time, I had fun decorating and putting the party together.