Of all the odd combo devices on the road today, this one actually seems to make some sense. Portugal-based NDrive has developed what it calls "the world's first GPS navigation system with a breathalyzer," according to NaviGadget.
There are other car breathalyzers that have been developed, of course, including some that prevent the engine from starting if the driver is past the legal limit. But the built-in GPS system might provide additional incentive for motorists to buy one of these portable devices, which appear to be destined for the European market for 200 euros, or about $297. As for the practicality, it obviously doesn't hurt to have a little help with directions, especially if you've had a few beers and have to hoof it.