X-link to the DRM-free thread for some new bundles:
Humble Book Bundle Start a Startup by Wiley contains DIY business books from the publisher of the popular “Dummies” series, with some titles especially suited towards tech startups, but most of general applicability to other ventures as well.
Also, StoryBundle's
The Aurora Award Bundle 3 contains only one non-fiction title, fellow MR member author Robert J. Sawyer's
Relativity, which collects a number of his essays and his old writing advice column from
OnSpec magazine (also available on his website, IIRC) in a handy single volume and is a nice offering if you're also otherwise interested in the rest of the bundle.