I could've sworn that I'd written about the classic game of Mornington Crescent at some point, perhaps in a column, but it appears that I never did. Odd.
I'm never sure how much to say about the game. I guess I could start by quoting one Mornington Crescent site:
Mornington Crescent is a strategy game played on the London Underground map, the aim being to move to Mornington Crescent.
On each move, a player moves to a station. Whoever moves to Mornington Crescent first wins. Players and commentators often provide commentary on how a move was achieved or how that move has been used historically or what prevented a better move, or whatever. You may find it useful to refer to an Underground map.
The game was popularized on the BBC comedy/game radio show I'm Sorry I Haven't a Clue. The unofficial (?) ISIHaC website provides a transcript of a novice game. Here's the opening move from that game, with explanation, just to give you a sense of how it's played:
The traditional opener, like the King’s pawn really—Oxford Circus, well in the zone, and gives you limited access to Northern parallels. But I suppose it is technically laying an off-side trap there.
That site also provides information about a great many Mornington Crescent variants. You can also learn more about the variants and terminology from the York Encyclopaedia Morningtonia, which is rather reminiscent in some ways of a game of Lexicon.