iBreath

It won't be long until you can plug your iPod into your steering column and the GPS function will drive you home. iBreath is an accessory from Apple that plugs into your iPhone or iPod Touch and measures blood alcohol levels via a blow wand that slides out. The iBreath also functions as an FM transmitter. However if you have to rely on this little piece of craftsmanship to know if you are drunk or not you might as well call a cab. iBreath retails for around $80 USD.