The Tough Guide to Fantasyland - Diana Wynne Jones
I've recently become quite interested in the TV Tropes wiki - partly because they keep linking to my Goodkind pages (thanks guys!) but mainly because I do love to see cheesy stereotypes pulled apart and mocked. For those who share my inclinations, you could do a lot worse than this book by Diana Wynne Jones, a glorious journey through fantasy's worst clichés, written in the form of a tourist guide.
Sewers. Despite the presence of so much REFUSE and SQUALOR, most CASTLES and CITIES seem nowadays to have Sewers. Their use, apart from the obvious one, is to provide access to or escape from the interior. Be warned. Many Tours make use of Sewers in preference to SECRET PASSAGES. Opportunities for WASHING afterwards are not always provided. Do not worry, though; most often, within half a day, all trace of stench will have vanished from you and your CLOTHING, almost as if the Management had forgotten about it.
Obviously, there's plenty of this to be had for free on the internet, from Evil Overlord to the Fantasy Novelists' Exam, but Wynne Jones is a proper writer and not just an internet parodist, and it's nice to have an entire book of well-written mockery. It's hit-and-miss in places, especially when lampooning fantasy clichés that have fallen out of fashion (for example, the frequent references to eyrie-dwelling clans, which may well have been a staple of mid-90s' fantasy but are not something I've seen much of), but there's still plenty to enjoy.