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 is free and also works on 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!