Dub

1. $20 or a multiple thereof.
2. (Music) A form of reggae music--usually instrumental--that originated in Jamaica in the early 1960s.

Usage

"C'mon, we could hang around the Bellagio and blow through a flag in the baccarat pit, or go the movies and spend a dub."

Less commonly referred to by poker players to a large multiple of $20, like $20,000.

King Tubby

A piece of music from King Tubby, one of the innovators of dub music in Jamaica: