I never got the whole carry-your-own-breathalyzer thing. If you are going to drive, just don't drink. And if you are not going to drive, who cares. I measure my alcohol levels by the next morning's hangover and/or the distance from the bed I wake up in to my house. But since some people have to drink and drive, the duiPhone breathalyzer hack for the iPhone seems like a good one. [Tellart—Thanks M.]