It's "Your Choice" for a discounted $9.99 ebook at O'Reilly
today (5/21). Discount code is FAVFA. You can pick any of the 2000 O'Reilly ebooks except for ones from Microsoft Press. O'Reilly books are mostly computer technology books, DRM-free, and you can download any (or all) of their three formats: mobi, pdf and epub. Some ebooks are also available in an Android .apk format.