Its no match for knocking back a few Diet Cokes in lieu of libations before getting behind the wheel, but if you cant avoid having a beer or two before driving home, getting a read on your blood alcohol content is an absolute must. Alcohoot, a smartphone-powered breathalyzer, will help you gauge your BAC and put a stop to further consumption before things get out of control. The $119 device, which boasts police-grade accuracy and plugs into your handsets headphone jack, is shipping now.