At a video game studio I worked at a while ago I hooked up some (real) traffic lights to talk to our CruiseControl.NET server to report breakages. But actually it was just for fun and didn't make any difference - the main thing was that we managed to instil into the culture a desire to always have a working build. Pretty much all the programmers were very proactive about fixing breakages, even when it wasn't a programming problem. It was sometimes possible for artists and level designers to break the build, and the programmers would always be pretty quick to respond and help them figure out the problem and to fix it or build in safeguards and tests to ensure they couldn't check in broken stuff.