lofg.com
Another well-designed site, with similarly good content (though rather less of it). The real plus though is the small and friendly message boards community, which I know longer have time to be a part of but which I would highly recommend. The matching pairs game is also quite good for a laugh.
The League of Gentlemen Website
Often quoted as being the nearest thing to an official League site. Excellent for news and has detailed episode guides and links to merchandise and so on. It is plagued by a very annoying moving pop-up window though... :(
The Local House
It's overly flashy, it's rather poorly designed and the ideas behind it are absolutely crazy. But i love it. This site has all the usual fan stuff (including a rather good gallery) plus one of the weirdest fanfics ever written - the second series of "Local Brother", a "Big brother" rip-off featuring several of the Royston Vasey characters. You'll never leave. Or at least, not for several hours...
league of gentlemen trading cards
Suitable for Top Trumps, and also for just looking at them and going "ewwww" at how high a snogability score she gave Edward. ;) A great deal of thought and effort has gone into them and it shows. Highly recommended, if only for the novelty.
Under construction - there'll be more to come!