@bythewell - That's really funny. I remember I had a teacher who was all about "magic" tricks and he had us all convinced he was a wizard. But, now that I think about, it was all prearranged stuff with other teachers and the adults assuring us it was magic, so we believed!
Personally, even as an adult I'd love a circus themed party as long as the food was right! There is nothing like cotton candy, corn dogs, and candy apples. Not the kind of food you'd eat every day, but if there is a party, you have a wonderful excuse to indulge!
And if you're the one making the treats, they are all easy to find or make.
In fact, this makes me want to have a circus themed party for my next birthday.