Play is work that you enjoy doing for nothing.
Source: In Quotations to Cheer You Up When the World is Getting You Down, by Allen Klein, 1991.
-- Evan Esar, (?? 1899-1995), Us humorist; He wrote Esar's Comic Dictionary in 1943, Humorous English in 1961, and 20,000 Quips and Quotes in 1968.