Step back a few years … I've often thought when I'm under a desk somewhere jiggling wires, is that some kind of audio feedback on ping would be useful: your server isn't responding, but when you re-seat the ethernet connector it comes back online; you have a messy, unlabeled switch to work through, so you unplug wires until the audio feedback stops, and you've located your machine. That kind of thing.
I've occasionally looked around the internet for such a tool and uncovered a couple of scripts and tools which don't quite work. I've even thought of writing my own script, but never quite got around to it.
But now the search is over. As part of Ubuntu/Gnome Desktop there is a hidden feature. You might have come across it before and missed it. A casual glance in System > Admin > Network Tools and you'll find all your favourite network diagnostic tools. Ping, netstat, nslookup, dig, finger, whois, etc. Well nearly all of them: it doesn't have the excellent mtr, but that's another story. So … as someone who's normally got a command prompt open somewhere, and who's used to the command line, I took an initial look at Network Tools, filed it as "Potentially useful", and went back to my old command line ways.
But look a little closer:flip to the Ping tab, and under Tools, there is an option to "Beep on Ping". Simple but Glorious.