While meeting with Microsoft Research's Ken Hinckley last week, we spent a good amount of time talking about gestures. He demoed a prototype application, called Scriboli, that took advantage of a multi-stroke gesture, allowing copy and move all in one stroke.

The videos below demo that functionality, as well as explores the idea of a dedicated button for one hand while writing with the other (which I absolutely love, btw). Whatever you wanted to know about gestures can be learned in these two videos, as well as in this research paper (PDF) authored by Ken, Patrick Baudisch, Gonzalo Ramos, and Francois Guimbretiere.

You'll be amazed the level of analysis that goes into gesture design.