Jazz is one of the modern genres of music that has been known around the world. In the terms of musicianship, jazz genre has been known as one of the most difficult to learn and play. Jazz can be heard in today popular music and it has extended to a point where it styles of playing sound completely unrelated to another.
As we talk about jazz, not everyone can make an extra effort to listen, at first. To some people, they found that jazz are too complex than some typical style we often hear at the radio (verse, chorus, verse, chorus et cetera) as it goes consistent all the time.
Literally, OFFBEAT is a music term meaning 'not following the standard beat' and since most of the jazz beat were sound catchy and it was 'off the beat' hence it becomes the name of this event.