isn't a stone-cold lock as the greatest "Why didn't I think of that?" idea in history, it's surely near the top of the pile. For those who don't remember and might be wondering just how big a thing ...

Before toy stores were stocked with pet plants, virtual pets and pillow pets, an advertising copywriter called Gary Ross Dahl was dreaming up the Pet Rock, a 1970s novelty toy craze since called a ...