Six-hundred episodes later, "The Simpsons" is still breaking ground

The classic Western series “Gunsmoke” rode off into the sunset after 20 seasons and more than 600 episodes. The record still stands -- no other scripted show in U.S. television history has made it to that mark. But that changes Sunday night.“The Simpsons” has been a fixture on Sunday nights since 1989. And Sunday night, viewers will make that familiar trip to Springfield for the 600th time, reports CBS News’ Dana Jacobson.For 28 seasons, millions have followed the a