In mid-1960s a Las Vegas-based Gin Rummy tournament was promoted by mailing flyers to players. The post office objected on the grounds that it was illegal to promote a "game of chance" (a lottery) through postal services. This case ended up in court. After listening to the testimony of experts that included statisticians and several prominent players, the US District Court of Las Vegas on February 23, 1965, ruled that Gin Rummy is indeed a game of skill.
(from "How to Win at Gin Rummy". Pramod Shankar, Ph.D. First Carol Publishing Edition, 1997. page 76.)