Here's one pair programming tool I'd like to see. Under Xorg it is possible to configure multiple keyboard/mouse pairs, so that a window clicked on by one mouse is active for its associated keyboard, and another window can be active for a different keyboard/mouse. But, I'd like to see some window manager support, such as changing the color of the title bar to represent which keyboard it is currently connected to.<p>This general setup is really nice when you are working with someone else, they are typing, and you need to do something on the side such as checking your email. Also works good with Emacs with two windows working on different parts of the same file.
I consider myself lucky that I haven't had to work with any pair programming tools in the last 15 years. I have, sadly, had to work with numerous waterfall, agile, scrum, and TDD tools. (I refer to their proponents.)