It is of course well known that there are four stations from which Mornington Crescent can be immediately declared if they are used as an opening move. These are Temple, Great Portland Street, Pimlico and Wembley Central. Opening with any of these would obviously lead to a one move game. The next shortest game is the so-called "Fool's Game" which is a three move sequence requiring very poor (or stupid) play from the first player (it is an interesting curiosity that all attempts to find a two move game have so far failed and it is believed to be impossible). The canonical example, though there other, more abstruse, examples of the "Fool's Game" is
but this has never arisen in "live" play since Highgate is a very poor opening and the Paddington - Regent's Park move in this situation is obviously suicidal. Button's Opening, often used in illustrative discussions of the rules is not valid in Tournament Play. Tutorial games aside, the shortest conventional games tend to be four to six moves and there are large numbers of such illustrative games available in basic textbooks or at the many "Teach Yourself Mornington Crescent" websites.
Hollinshead's Chronicles' famous game between Henry VIII, Thomas Cranmer and Katharine Howard appears to be a two move game but see the entry on the Royal Shunt for an explanation.
See also: Longest Game.