Gnome15 comes with many plugins for displaying various info on your keyboard, such as a Cairo Clock, Notify LCD, a calendar integrated with Evolution, RSS reader, volume monitor, display the weather (using Google API),
Keyboard Status Monitor (key-mon) is a Linux tool for displaying keyboard and mouse status on the screen, ideal for creating screencasts.
Once upon a time… I sat beneath a person who tried to show me something on his GNU/Linux desktop. As he noticed, he needs to copy a password from his Windows machine (was it OS X?), which was standing close, I waited for him to copy and paste by using his eyes. But hey: He just moved his mouse across the boarder of his screen and the mouse pointer appeared on the screen of the other computer.
KeyTouch is an application designed to allow you to make full use of all the special function keys on your keyboard, whether the hardware supports Linux or not. It's a great idea, especially with all the multimedia applications that come standard with today's PCs. But as is often the case, the devil is in the implementation details.
There are many occasions at which a user needs to use two computers at the same time, even with two different operating systems, all in the same desktop. One of the most annoying things that might happen is that you will need to use a different set of keyboard and mouse for each computer with the resulting waste of space on your table.