MADISON, Wis. (AP) – A real clown is taking over as leader of Circus World.   A “boss clown,” as a matter of fact.  Scott O’Donnell, who worked as “boss clown” for the Ringling Brothers and Barnum and Bailey Circus in 2006 has been selected to take over as executive director at Circus World starting on Sept. 15.  O’Donnell’s selection from a field of 25 candidates was announced by Circus World on Monday. He previously served as Circus World’s operations manager from 2002 through 2005. After his work as “boss clown” and talent manager at Ringling Brothers, he also worked as vice president and general manager for the Big Apple Circus in New York.        O’Donnell is replacing Steve Freese, who left Circus World in June after six years at the helm.