You probably don't know RESTPrint
As Web developers, most of us have either utilized a REST Api to integrate with services like Flickr, Facebook, Amazon or Twitter, or created one to allow others to integrate with our systems. REST (REpresentational State Transfer) on the surface, seems to be simple which perhaps explains why so many REST api's are largely incorrect and not RESTful at all.
Sensio labs has been kind enough to post videos of the presentations from the Symfony Live San Francisco conference, which included this fantastic presentation from David Zuelke, entitled Designing HTTP Interfaces and RESTful Web Services. David explains the philosophy of REST, explains HATEOS, the Richardson Maturity Model, and lays out the rules for creating a good REST interface, illustrating with examples of bad ones. No matter your development language, platform, or framework choice, this is an excellent talk that's well worth your time.