The 20% Doctrine
On the suggestion of +Louis Gray, I recently started reading The 20% Doctrine by Ryan Tate. The book is a short but entertaining read outlining a couple of skunkworks projects that eventually became valued additions to the sponsoring company and in some cases became the sole focus. In the 208 pages, Tate covers how Flickr, GMail, Google Reader, Adsense, and several other projects thrived despite facing fierce opposition in some cases. While the book does give some helpful tips, I think it's more important to see it as guidebook and not a manual. It can send you in the right direction and give you hope to proceed but it won't give you the solution to every problem you'll face.