Originally the Green Eggs and Ham style skit with George Bush refusing to eat broccoli was written by Paul Rugg for Animaniacs, but by the time it was ready to be produced Bush was no longer president.
You'll Be the Leader of the United States Sung by Histeria! Kids Chorus [parody of "YMCA" written by Henri Belolo (uncredited), Jacques Morali (uncredited) and Victor Willis (uncredited)]