Zzzzzz, later just Z, was a dial-a-joke service active in the 1970s and early 1980s. Started by Bob Bilkiss (1949–1989[1]) of West Los Angeles in 1970, it operated from the 213 area code and was named so to appear last in the Los Angeles telephone directory. Emerging from a wave of dial-a-joke numbers in Los Angeles in the turn of the 1970s,[2] Zzzzzz enjoyed a high level of popularity in its day. For several years, it was the busiest residential telephone number in the United States, if not the world.[3]