I think it's safe to say that nobody reads the MLA Style Manual for fun. After all, the aim of a style guide is to inform, not entertain. So it's remarkable that Guardian Style, by David Marsh and Amelia Hodsdon of England's Guardian newspaper, succeeds in doing both.
Mind you, not all the information in this book can be regarded as essential. (How often are you called on to spell awopbopaloobop alopbamboom?) But the usage advice is generally sensible, witty, and concise.
For your information and amusement, here are some of my favorite entries from the third edition of Guardian Style. . . .
For the complete article, see The Best of the Guardian Style Guide.