Franklin Roosevelt's selection of the sunny Happy Days Are Here Again debuted at the 1932 Democratic Convention — by accident. Judge John E. Mack, the man who introduced Roosevelt, delivered a bland clunker of a speech and walked off stage to the originally chosen song, Anchors Aweigh. Roosevelt's political advisors were so upset by the awful performance that they demanded a new song be played before the candidate's speech. They selected Happy Days Are Here Again, from the 1930 musical Chasing Rainbows, making Roosevelt the first President to pick a pre-existing song for his campaign and handing the Democratic Party their unofficial theme song for years to come.
—By Claire Suddath