mystery fruit

When I first posted this I said:

I have no idea what sort of fruit this is. My plant ID skills are pretty bad at the best of times, and I don't exactly improve while visiting unfamiliar tropical locales.

If you know what we're looking at here, please feel free to leave a comment.

The mystery is solved now, thanks to yus_prinandy on Flickr. This is a noni fruit (Morinda citrifolia). They aren't supposed to be very tasty in this form, and they're said to be rather stinky (although I didn't notice that part). Despite that, it's a traditional medicinal plant, and the University of Hawaii's College of Tropical Agriculture has a site full of info on growing them.