By Richard Lederer and Caroline McCullagh

January 24, 2014 (San Diego)--Tinkering is a time-honored American pastime. Many men and women can’t leave well enough alone. They’re always trying to create something or improve something. As with most creative people, they benefit from the work of those who came before them, but they add that little spark of genius that can take their invention figuratively or literally into the stratosphere. Here are some of our best: