A circus is commonly a travelling company of performers that may include clowns, acrobats, trained animals, trapeze acts, musicians, hoopers, tightrope walkers, jugglers, unicyclists and other stunt-oriented artists. The word also describes the performance that they give, which is usually a series of acts choreographed to music and introduced by a ringmaster.
Common acts include a variety of acrobatics, gymnastics (including tumbling and trampoline), aerial acts (such as trapeze, aerial silk, corde lisse), contortion, stilts and a variety of other routines. Juggling is one of the most common acts in a circus; the combination of juggling and gymnastics is called equilibristics and include acts like plate spinning and the rolling globe. Acts like these are the some of the most common, and the most traditional. Clowns are common to most circuses and are typically skilled in many circus acts (source: Wikipedia).