This small hack makes the Thinkpad light blink twice whenever the nickname is mentioned in a non-visible buffer. To take full advantage of it when not in Emacs it is better to change to some non-IRC buffer, since it will not signal the activity if the buffer is visible, even if the Emacs frame isn’t.

It depends on the ibm-acpi (thinkpad-acpi in version 2.6.22 and above) to provide the “/proc/acpi/ibm/light” interface, which makes it Linux-specific.

(defun thinklight-control (cmd)
  "Turn ThinkLight on/off, depending on the value of the string cmd"
    (condition-case nil
	(write-region cmd nil "/proc/acpi/ibm/light" nil 1 nil nil)
      (error nil)))

(defun my-rcirc-notify-thinklight (proc sender response target text)
  "Blink the ThinkLight when someone mentions nickname"
  (when (and (string-match (rcirc-nick proc) text)
	     (not (string= (rcirc-nick proc) sender))
             (not (string= (rcirc-server-name proc) sender))
	     (not (get-buffer-window (current-buffer) t)))
    (dotimes (number 2 values)
      (thinklight-control "on")
      (thinklight-control "off")
      (sleep-for 0.1))))

(add-hook 'rcirc-print-hooks 'my-rcirc-notify-thinklight)