This article about the redneck society states that you might be a redneck, if you think it is called "duck tape" instead of "duct tape." The redneck society page says it as well.
Well, if you call it "duct tape," you are wrong. The trademarked name for the tape is actually "Duck Tape." It was invented during world war two by Permacell, a division of the Johnson and Johnson Company and was used to seal American ammo cans against water. The resulting tape was nicknamed "Duck Tape" for its ability to repel water.