TIME magazine has a piece on the latest fear of security experts--guns disguised as mobile phones.
"Sources tell TIME that cell-phone guns, some of which have been seized in drug raids in the Netherlands, England and Germany, have been cited in several federal security alerts over the past year, the most recent just over a month ago. Though heavier than normal phones, the lethal ones look nearly identical. The hollowed-out devices, made in Croatia, are fired by punching buttons on the keypad and can shoot four .22-cal. bullets in rapid succession."
Unlike the bad press camera phones have gotten as of late, this sounds like a genuine fear. Look for phones to be checked just like laptops (have to turn them on).
Here is a video of a cellphone gun in action.