I think it's tragic that you've visited the home of this wonderful game and yet never experienced it. The broadcasts I mentioned have been on BBC Radio 4 as part of the long running "I'm sorry I haven't a clue" - a show that has been going for about 30 years and that still has some of its original participants (who have of course become revered masters of the game). It's fair to say that this programme has done more to popularise the game in recent decades than anything else.
Mornington Crescent is a turns based game which is ideally suited to radio, or email, or face to face confrontations, or forums like these. At least two people are needed to play it (though I have seen MC robots on the web for a solitaire version against the "AI"). I have seen many more than that play a single game. Four people play it on the radio show and that makes for a quick and lively game.
To an onlooker, it seems that each player's turn results in one thing: the announcement of a place name. Nowadays these place names are usually (but not always as it depends on the rule set being used) the names of London Underground railway stations as could be found on a "Tube Map". Of course there are many other things that are said, usually discussions of the finer pointers of the rules, but the important thing is always the progression of place names. The game ends when one player announces "Mornington Crescent". There are no second places.
I recommend that you investigate via Google, though I've noticed that some of the sites listed are not quite up to date. (There is usually a big student interest in MC and they tend to use their university sites.) It's of course well worth a trip to "Encyclopaedia Morningtonia"...
http://madeira.physiol.ucl.ac.uk/people/jim/mc_em.html
That really is not a beginner's tome, but you'll get a flavour of the game from it.
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"Life shrinks or expands in proportion to one's courage" - Anais Nin
[This message has been edited by stormerne (edited February 27, 2001).]