I'm developing a small Windows application that connects to your Google Reader account, retrieves the most recent/unread entries, formats then as an ebook (mobipocket file) and send them to your kindle so that you can read them while being offline. (I'm using it mainly in the subway).
It's free and available at sourceforge:
https://sourceforge.net/projects/greader2kindle/
The application is still in its early stage, so I'll greatly appreciate all feedback about bugs or improvements suggestions.