The 70 Percent Solution [the broken link was removed] by John Battelle, an interview with Google CEO Eric Schmidt:
Google is also well know for the 20% rule for technical staff [the broken link on Google’s site was removed]
Google engineers all have “20 percent time” in which they’re free to pursue projects they’re passionate about. This freedom has already produced Google News, Google Suggest, AdSense for Content, and Orkut – products which might otherwise have taken an entire start-up to launch.
Both models attempt to assure significant time is devoted to new ideas.