When you're in a strange city it's easy to get lost, but you don't want to miss the sights because you're glued to a map or GPS device. German and Swedish researchers may have created a solution - a cell phone that can give you GPS directions simply by heating up or cooling down the handset.
It uses a Peltier device to change temperature - the warmer the unit, the more on-track you are, but take a wrong turn and it will cool down. This odd feature could also be used in other ways, like telling you how important a call is - if it's your hot girlfriend it could get toasty warm to tell you to pick up, but if it's your boss then it could ice up to tell you that it's best avoided. [New Scientist]