As a big coffee nerd, I was so excited when my sister and brother-in-law came back from Indonesia with some fresh beans for me. The crown jewel was a small bag of precious kopi luwak, which has been called the "most expensive coffee in the world."
What makes luwak so amazing (and costly) isn't the beans or where it's grown, it's how it's processed. To put it nicely, the bean goes through the normal coffee fermentation process through the digestive tract of a small mammal, the Asian palm civet. To put it another way, it's cat poop coffee.
The reviews I've read of luwak run the gamut from "gross" to "interesting" to "incredibly smooth." Given the enormous buzz around luwak, and the resulting scramble of Indonesian farmers to produce more and more of this expensive product, quality can vary widely. There are several reports of civets being kept in very inhumane enclosures and force fed coffee, instead of being harvested naturally. My sister tells me that the farm they purchased our coffee from ethically harvested their beans.
I made a batch for myself and some guests to try last night. We all agreed that it was exceptionally smooth, a balanced medium roast with a pleasant fruitiness. I am generally not fond of fruitier, lighter roasts, but I really enjoyed the luwak coffee. I would gladly have some in the future.
If you have an opportunity to have a cup of kopi luwak -- and you are reasonably sure it was produced in an ethical way -- I highly encourage you to try it.