A friend of mine has started a blog as part of her school work. Over the years, I have instilled in her the religion of backing everything up. Having learned well, she asked me "so, how do I back up my blog"? After we determined that it was a Blogger blog, I set up a test blog there so I could find the right part of the admin settings...
...and there are none. You can't back up your blog. Note to Google: let people do this easily. You are teaching people bad habits if you don't make offsite backup quick and easy. For many people, a blog is their creative outlet. We tell them to back up the writing on their computers; they should be able to back up their writing on the Internet.
After a bit of searching, I found Blogger Backup Utility. It only works on Windows, so my friend can't run it, but I could run it for her. I will remember to do so each month (along with all my other backups). It produces an Atom feed of her entire blog. The makers get extra points for the Atom validating. (Updated: I was wrong about the HTML content being borked. Thanks to Sam Ruby for explaining why.)