Riff, or improvisation, is a spontaneous musical creation where musicians generate melodies or rhythms on the spot. This practice is common in genres like jazz, blues, and rock, allowing artists to express their creativity and showcase their skills. Riffs can be built upon existing themes or completely original ideas, often enhancing the overall performance. Improvisation encourages collaboration among musicians, as they respond to each other's playing in real-time. This interaction can lead to unique and unexpected musical moments, making each performance distinct. Notable improvisers include Miles Davis and Jimi Hendrix, who are celebrated for their innovative approaches to riffing.