X-link to the DRM-free thread for some new bundles:
Humble Book Bundle Java presented by O'Reilly is full of DIY computer programming books for that language from the popular tech publisher, at every level from just beginning to advanced applications for various adjacent technologies.
Also, the
Humble Book Bundle Stellar Sci-Fi & Fantasy presented by Tachyon contains a non-fiction book of essays from Cory Doctorow at the 3rd tier, if you're interested.