Nagios Traffic Light
I have been using Nagios on and off for a few years now and one of the things I saw early on was an idea to have a physical traffic light accepting it's state from Nagios.
Recently I couldnt find any reference to this but I have now come accross this:
NAmpel - the Nagios Ampel Project
This looks like a fun/must have project.
I've thought about doing this with one of those premade PIC controller boards which has a USB input. You could do all sorts of fun things with them - such as having a mini LCD which could tell you various things.
Just not got the time or money to experiment with it.