Have you been wanting to try Amazon’s new ebook format (but don’t own a Kindle Fire or Windows PC). I have some good news for you. Calibre, the open source ebook management tool, can now read and display KF8 files.
The update just came out this morning, and it includes a number of bug fixes as well as new support for 2 Android tablets. But it does not include the ability to make KF8 ebooks just yet; that will be coming in a future update.
On a related note, there aren’t very many KF8 ebooks available outside the Kindle Store, so you might need to make your own. You can download the Kindle Previewer from Amazon and use that to convert an Epub, if you like, or you can try one of a handful of demos that I have uploaded over here.