(I'm misunderstanding, aren't I?)

Yes. :) "Compatible with Cucumber" is a plus for Ruby and a minus for Python. Though, looking further into the Cucumber docs, it looks like there's a way to use it with some other tools for language-agnostic, outside-in Web application development; I may end up trying this, and if I do, I'll report back what I find out.

Thanks for the tip on the tutorial, I'll have a look. :)