Josephine de Beauharnais (1763-1814) was the Empress of France from 1804 to 1809. She married Napoleon Bonaparte in 1796, but he got a divorce in 1809 because they had not produced any children together. According to an old story, Napoleon once said "Not tonight, Josephine" when he refused to have intimate relations with her, and now this phrase is sometimes used in a humorous way. However, there's no evidence whatsoever that Napoleon ever uttered these words because there's certainly no printed record of them in any language in his lifetime.
Why the phrase came to be coined isn't clear. It might have been originated as a piece of anti-Napoleonic sentiment.
Not Tonight Josephine is also a historical trivia game. The game includes glass bead gaming pieces, a colourful board and question cards, many of which are also in colour. There are two boxes for the cards, and cardboard coins, as well as dice.
There are 30 different question categories on the board, including traditional ones such as "Ancient History", "Royalty" and "American Civil War" and others of a quirky nature such as "Famous Exits", "Cockney English" and "Submarines".
Not Tonight Josephine is also the name of a rock band and of two songs: "Not Tonight Josephine", performed by Slade from the album We'll Bring the House Down and "Yes Tonight Josephine", which is a single by Johnnie Ray.