Have you ever found yourself navigating through code and ending up at an Interface, instead of the concrete implementation you were hoping for? During Yun Cheng's talk - MVP The Life-Changing Magic of Tidying Up Your Presentation Layer (at 360 AnDev), her and her team uncovered that exact command.
What is it?
The Go To Implementation(s) action, which will take you to the concrete instance of and Interface. If more than one concrete class exists, a picker will be displayed that will let you choose which instance to go to.
How do I use it?
Position your cursor on an Interface method and press
⌘+⌥+B. Note: you can do this from the Interface class itself or you can do this from a invocation of the method.