When passing through metal detectors you're always asked to empty the change from your pockets, but do security personnel really look through your coins? Probably not, which is why this fifty cent piece with a hidden knife blade could be really useful.

Whether you find yourself in the trunk of a car bound and kidnapped by baddies, or in need of some easy way to peel a particularly thick-skinned orange, the sharp steel blade stashed inside this fifty cent coin is endlessly useful. And as long as no one stops to closely examine the $39 coin and the obvious seam where it splits in two, you don't have to worry about it ever being confiscated. [Shomer-Tec]