Scott Berkun's (writer of Myths of Innovation, etc.) new book Mindfire is free to download on his blog for the next 1 day and 22 hours in PDF, ePub and Mobi formats. All you have to do is sign up for his email list and you can download it immediately.
I already pre-ordered his book through Kickstarter and while I wait for my Kindle version to arrive I'll sign up and a copy in ePub format to read on my iPad. I will be mentioned in the book in the Acknowledgments section so take a look!