Show key presses via dribble

record.el

(defun start-recording ()
  (interactive)
  (setq auto-revert-interval 0.5)
  (auto-revert-set-timer)
  (when (file-exists-p "keys.log") (delete-file "keys.log"))
  (delete-other-windows)
  (split-window-vertically (- (window-height) 5))
  (other-window 1)
  (nlinum-mode -1)
  (find-file (expand-file-name "./keys.log"))
  (toggle-truncate-lines -1)
  (text-scale-adjust 3)
  (other-window 1))

(defun stop-recording ()
  (interactive)
  (open-dribble-file nil)
  (when (file-exists-p "keys.log") (delete-file "keys.log"))
  (when (get-buffer "keys.log") (kill-buffer "keys.log"))
  (delete-other-windows))

Requires http://www.emacswiki.org/emacs/AutoRevertMode