Adam Jacot de Boinod celebrates the "joy of foreign words" in a new book called The Meaning of Tingo. The BBC discusses the book and some of its many fascinating examples here. (Neil Tweedie also covers the book for the Telegraph in this recent review.) It is amazing how and why languages create new words--their creation reflects both the culture and the linguistic boundaries of the given language. English loves new verbs, for example. We can make a verb from almost any noun. German loves compounds and has some great ones de Boinod mentions like Dragonfutter, "literally translated as dragon fodder - the peace offerings made by guilty husbands to their wives." Readers of the BBC have written in examples of their own, including monobrow from English.
(One note: While koshatnik in Russian does mean "a seller of stolen cats", it also more frequently means someone who loves cats and has a female form koshatnitsa, simply "cat lady.")
Also, via Maud Newton, books left on NYC's MTA (Travelers Diagram). Lots of Lolita and Harry Potter and the Half-Blood Prince. Probably offerings, rather than forgotten or abandoned books.