"To join the circus" means to become part of a chaotic or unconventional environment or situation. It can also mean someone is seeking excitement or variety in their life by being part of something different or unusual. Full definition
My worst moments are after the coffee where's off and my oldest two of four come to join the circus after school and they need help with their homework.. (crappypictures.com)
Try do dress up more decent and choose cool colors that would enhance your personality because remember you are dressing up to impress a lady not joining a circus. (onluxy.com)
Then one day a young man who used to be the girl's lover joins the circus and tries to help her remember her past. (mutantreviewers.wordpress.com)