I don't usually do news and current events here, but I'm making an exception for the CWE/SANS Top 25 Most Dangerous Programming Errors list. This one is important, and deserves a wide audience, so I'm repeating it here — along with a brief hand-edited summary of each error.
If you work on software in any capacity, at least skim this list. I encourage you to click through for greater detail on anything you're not familiar with, or that piques your interest.
A GNU-FDL book on algorithmic graph theory by David Joyner, Minh Van Nguyen, and Nathann Cohen. This is an introductory book on algorithmic graph theory. Theory and algorithms are illustrated using the Sage open source mathematics software. To get an overview of the book, you can view the table of contents as shown below or download the complete book.