I liked the mouse gesture of Windows 7 to minimize all open windows except the active one. Can I have that kind of gestures to use in Unity.
or What are the mouse gestures available for Unity?
For your general question take a look at "What are Unity's keyboard and mouse shortcuts?"
For your special question I suggest Easystroke:
Easystroke is a gesture-recognition application for X11. Gestures or strokes are movements that you make with you mouse (or your pen, finger etc.) while holding down a specific mouse button. Easystroke will execute certain actions if it recognizes the stroke; currently easystroke can emulate key presses, execute shell commands, hold down modifiers and emulate a scroll wheel. The program was designed with Tablet PCs in mind and can be used effectively even without access to a keyboard. Easystroke tries to provide an intuitive and efficient user interface, while at the same time being highly configurable and offering many advanced features.(source)