Via Gawker, who advises us to "[a]lways take your gun out of your pocket before you take off your pants" (emphasis in original):
A man in Tennessee has learned the hard way that when undressing, any guns one has in his pants should be removed from the pants before they are removed from one's body. He reportedly took off his pants, with his gun still in the pants, and placed them on a dresser, at which time the gun went off. The bullet hit the man in his chin and then lodged in his neck.
Read the full story at the Johnson City Press.