LOS ANGELES (The Associated Press) -- The documentary "Being Elmo: A Puppeteer's Journey" opens this week, about every toddler's favorite red monster and the man who brings him to life, Kevin Clash.
One of the joys of watching Clash in action -- besides marveling at how effortless he makes it all look -- is seeing how seamlessly he relates to both children and adults. And the segments he does with celebrities, as Elmo learns a lesson or explains a new word, are among his best. So here's a look at five of the greatest celebrity appearances over the four-plus decades "Sesame Street" has been on air. As the mother of a 2-year-old son, compiling this week's list was one of the most enjoyable yet.