Xpra gives you "persistent remote applications" for X. That is, unlike normal X applications, applications run with xpra are "persistent" -- you can run them remotely, and they don't die if your connection does. You can detach them, and reattach them later -- even from another computer -- with no loss of state. And unlike VNC or RDP, xpra is for remote applications, not remote desktops -- individual applications show up as individual windows on your screen, managed by your window manager. They're not trapped in a box.

A tiling tabbed window manager designed with keyboard users in mind.

Stumpwm is a tiling, keyboard driven X11 Window Manager written entirely in Common Lisp.

This program monitors the keyboard and echos each key pressed on the keyboard.
xspy takes advantage of an oversight in X Windows (R5 & R6) to find out about keypresses even in "secure mode". It works by polling the keyboard, by default every hundredth