X-link to the DRM-free thread for some new bundles for programmers:
Humble Book Bundle UNIX presented by O'Reilly contains all sorts of helpful DIY getting started/advanced reference titles for various UNIX tools and a couple of guides to popular variants such as Linux and Mac OS X.
StoryBundle's
Pico Game Bundle contains a number of non-fiction titles about programming your own video games (including a download of the titular fantasy gaming console software), some behind-the-scenes books about the making of various specific games, a quasi-academic title about the history of Dungeons & Dragons, and more. Their
2016 NaNoWriMo Writing Tools Bundle containing all sorts of advice for the aspiring author, expires soon.