I like this idea a lot; however, I don't like beeps.  Ubuntu (and possibly other linux distros) now supports desktop notifications via Notify OSD.  So instead of having the other machine ssh to me and beep, instead I use a utility called "notify-send" to create a desktop notification pop-up.  You can install notify-send on ubuntu using:<p><i>sudo apt-get install libnotify-bin</i><p>Then call notify-send like so:<p><i>notify-send "Back to work."</i><p>The text can be anything you want, and you can also supply a summary, an icon, etc.