I have been using this program for about a month now, and I LOVE it. If you are unfamiliar with gestures (as seen in the excellent browsers FireFox and Maxthon) they are mouse movements that trigger events.
After setting up gestures in photoshop and using them for a while I really have trouble working without them. For example, all I have to do to crop is hold the right mouse button and draw an "x" (see below).
It lets me use all those key combinations that are hard to hit one handed (like CTRL+SHIFT+F6) for commands and filters I use all the time that don't already have hot keys without taking my hand off the mouse or having to traverse menus. Download here
and best of all it's free!