Play-Doh is one of those revolutionary toys with surprisingly mundane roots. In the early 1950s, Joe McVicker sent some solid, mashable wallpaper cleaner to a classroom after learning that children often found clay too difficult to handle. It was a smash with the kids, and McVicker graciously offered to send shipments to all Cincinnati schools. It didn't take long to realize that the substance had more potential as a toy than as a cleaning product. (We've since played with more than 700 million lb. of the stuff.) By 1956, Play-Doh had its oddly spelled name, and stores like Macy's and Marshall Field's took notice. Colorful versions of it soon followed, with a full eight-color palette by 1980. Later iterations have included glitter and glow-in-the dark Doh for those who need a little extra oomph in their goo.