Todays e-book offer is Expert Oracle Database Architecture: Oracle Database Programming 9i, 10g, and 11g Techniques and Solutions, Second Edition - details at http://www.apress.com/book/view/9781430229469
At $10, as an e-book from http://www.apress.com/info/dailydeal
If you like me deal with Oracle databases (even if only ocassionally), it is a good book to get!