Time for a trip to the circus. Start with the name of the circus. It doesn't have to appear in the finished piece, but decide on something to guide you through the rest of the exercise. Decide on what kind of circus it is, as well. Is it a freak show? A collection of the wonders of the world? Maybe an all-clown circus. Perhaps you can experiment with different flavors for the acts as well. Instead of clowns and trapeze artists, it's a collection of oddities, or home to The World's Saddest Man and the The World's Silliest Dog. It could be a steampunk circus, or circus from the 25th Century. Take a trip to the circus, or let it narrate itself. Flesh out the lives of the inhabitants, find out what they want or need, what they dream about night after night, under the big top.
Nothing is too grand or too small. Flea circuses and underground circuses are welcome here.
Take a look at the lyrics to Circus by Tom Waits. Could be a song. Could be a poem. Might be both.