I second the BlackBerry PlayBook's implementation of gestural commands. The PlayBook does not have Home, Back, or other command buttons on its front face yet it is very easy to return to the main menu or switch to another open application. A single-finger swipe is used to scroll within an application, to switch from one app to another, and to return to 'Home'. The key ingredient that makes all of this work intuitively is the Playbook's bezel. That black band of glass surrounding the image, a dead-zone on most other devices, is actually a live part of the PlayBook's user-interface. Swipe from the bottom frame upwards (effectively, starting from "outside the app") and you reduce the current app to a window and expose the main menu; you're returned to 'home'. Swipe from the top frame downwards and you expose the app's menu. Swipe from the right frame towards the center and you switch to the next running application. Same applies if you start from the left frame. Naturally, all up/down and left/right swiping within the boundaries of the frame (i.e. withing the visable app) controls vertical and horizontal scrolling. In addition, many UI items subjected to a swipe respond with appropriate "physics" (i.e. acceleration/deceleration/momentum) thereby an imparting a sensation of interacting with real-world objects in a fluid medium. One could argue that the frame constitutes four buttons. However, operating a button is a different physical interaction compared to a swipe. The beauty here is that the 'button' has been replaced with a swipe thereby maintaining a consistent experience.