Both of these came to my attention from following inkmesh on Twitter. They also let you know about free books at other places, like Sony or Kindle.
I hope it's okay that I'm posting this information, since theoretically, it can be gathered elsewhere.
Shakespeare in an Hour by Christopher Baker --a brief biog of the Bard, along with information about his time period and other details
and
Shadow of Power by Steve Martini. Make sure you get the one marked "free" and not the pay version, which oddly, is still on their site. Note: I can't confirm that this is not just a sample, as I'm not familiar with the book.
No idea how long either is free for, they are not "Free Friday" books.
-Rob