I am currently reading Is That a Fish in Your Ear?: Translation and the Meaning of Everything by David Bellos, which is about translations (NY Times has a book review of it here).
While reading the book, I couldn't help think of this sticker which I took a picture of some months ago (the black one), since it is a good example of the problems with translations.
The sticker was in a Danish bar, and translated into English it would be "klistermærke swine" - yes the first word would be the Danish word, since the word sticker is not Danish, but English.
Of course, translating the text would make absolutely no sense, because the whole point is to make a linguistic joke. "Sticker" sounds similar to the Danish word for snitch ("stikker"). Snitches are often referred to as "stikker svin" which means "snitch swine".
As people can see, the brilliance of the sticker text looses a lot in translation (well, all of it, really), but trust me, I laughed out loud when I saw it.