I just came across a neat little extension for my FireFox browser. It's a mouse gesture catcher that catches your mouse gestures and uses them to execute rule-based actions. For instance, if I hold down the right mouse button and move right (while holding) I open up a given link in a new window. You can set up both built in and customized gestures.
It's a great idea but I am not sure how useful it would be. I immediately got rid of 99% of the default gestures. I either do not do them or do them in another, faster matter (ex. Using the fourth mouse button to go back in the browser). Right now, the most useful one I have is the click-and-move-down which views the source of the page. As a programmer, I am always viewing the source of my pages to debug. This is great, especially for Frame pages.