Complex sentence: These are also called reprises or run-ins by many and in today's circus they are an art form in themselves, originally they were bits of "business" usually parodying the act that had preceded it.
Split into simpler sentences: These are also called "reprises" or "run-ins" by many, and in today's circus they are an art form in themselves. Originally they were bits of "business" usually parodying the act that had preceded it.