Go here: http://www.ereader.com/promo
There will be a new ebook every day in December.
Today: The 9/11 Comission report.
You need a credit card to register, and then the same credit card to "unlock" you book after download. (If you are the tinfoil hat type, move on to the next deal...)
I will update this thread with each day's book as they come.