Gestures are the big thing these days, with Apple's new operating system for the Mac relying heavily on them. Glissando ($0.99) is a new app that lets you control music playback with gestures. The app emphasizes simplicity with a set of intuitive gestures that allows you to play and pause, skip tracks, fast forward, rewind, and more — without glancing at the screen. For example, you can toggle pause and playback by simply tapping anywhere on the screen. Or swipe to the left or right to listen to the next or previous track.