Oh, Interweb. Thou art a boundless source of amusements.
So, some well-meaning fellow named John DiGaetani put together a fine book about Richard Wagner's gloomy, interminably long and possibly brilliant Ring Cycle. Good for him. Unfortunately, he gave it the title Penetrating Wagner's Ring, setting off a veritable festival of double entendre on Amazon.co.uk.
Check out the review section for the book's Amazon listing. Amazing. Here's a sample:
Penetrating Wagner's Ring is a wonderful way to spend many a lazy afternoon, or even the odd fun-filled weekend! At first I found it difficult - Wagner's ring is not the most accessible piece - but as time passed, and I became more comfortable with the hole idea, I found myself sinking into Wagner's ring more and more, and now, it is one of my favourite things to do. For those who have never experienced Wagner's Ring, I highly recommend it - it is a life changing experience, and once you encounter the joy and pleasure of the ring piece you will most definitely never go back! Penetrating Wagner's Ring made me the man I am today - everyone should try it, and don't worry if you find it difficult, it gets easier with practice. My one issue with penetrating Wagner's ring is the cost - I know penetrating wagner's ring is popular, but I think gaining a deeper insight into Wagner's ring is beyond most people at this price.
Gold! Thanks to MN for the link.