I’ve been using CruiseControl for about half a year now, and the Ant sound task works well. Just crank up the speakers and collect a directory of Success and Failure sounds. It’s hard to ignore the audio track from the Psycho shower scene when a build fails, or a snip of the Indiana Jones theme music when it passes.
Our build machine recently switched to a rack mount in the server room, so I wrote a little Ant task that loops and parses the CruiseControl RSS feed (mentioned in Pragmatic Project Automation) and sets the build status based on that, playing a set of sounds on a workstation locally. We get punk covers of show tunes (from Me First and the Gimmie Gimmies "Are a Drag") and Office Space quotes when the build fails. The sounds are different from our usual workstation collection, and nothing says you missed a file check-in or config change like Bill Lumberg saying "Uh… we have sort of a Problem here.." at max volume. :)