First lady Michelle Obama and comedian Jimmy Fallon compete at tug-of-war at the White House during a taping of Mr. Fallon's "Late Night" program Jan. 25. Mrs. Obama has made the talk-show rounds while promoting her "Let's Move!" fitness campaign. (The White House via Associated Press)

First lady Michelle Obama and comedian Jimmy Fallon compete at tug-of-war at the White House during a taping of Mr. Fallon's "Late Night" program Jan. 25. Mrs. Obama has made the talk-show rounds while promoting her "Let's Move!" fitness campaign. (The White House via Associated Press)