'The Simpsons' turns 400

Happy 400th, Homer

And to think, Homer once worried that he wouldn't live to see his children die. But here he is, clocking in at 400.

"The Simpsons'" 399th and 400th episodes air Sunday on Fox, starting at 8 p.m., and the yellow-skinned patriarch, not to mention his blue-haired wife and spiky-headed children, is none the worse for wear.

Over the course of 18 seasons, with at least one more in the works, the 23-time Emmy winner has become both a mainstream hit and a cult classic, pulling in millions of viewers and attracting the sort of fanatical attention to detail that would make any Trekkie proud.

The animated sitcom--only the fourth scripted primetime series in history to reach the 400 episode mark--has spawned reams of episode guides, trivia books, academic studies and treatises on "The Simpsons'" influence on television, language, philosophy and pop culture in general. And speaking of the national lexicon, "D'oh!" made it into the Oxford English Dictionary in 2001.