I can see all the fun you could have during karaoke with this hack. Randy over at fffffatlab built this breathalyzer microphone.
The breathalyzer microphone is a system for the inconscpicuous collection of blood-alcohol content level data sets. In other words, you can measure a person’s sobriety with a device, that for all intents and purposes, looks no different than a standard microphone.
There is a step-by-step instruction for building your own on instrutables.