Is it possible to create custom gestures for Macbook Pro Trackpad and Magic Mouse to custom actions? For example to close a window or launch some application.
Not so sure about the Magic Mouse, but for the trackpad there are a number of options.
jitouch looks very customisable, but costs.
BetterTouchTool works with the Magic Mouse. It gives you a PrefPane that lets you assign loads of gestures with loads of actions, including opening Apps. I'm sure it has capability to close windows as well.
Hope this helps!
Another useful tool is MagicPrefs, although it really shines with the trackpad.