"It's October, So It Must Be Time For a Surprise"

"In the end, the Republican plan didn't work and the letters were never released. Why? Perhaps because Wendell Willkie decided it was beneath him. Perhaps because the Republicans were worried it would cause a backlash. Or perhaps it was because Willkie had a mistress and FDR made it clear that two could play the October Surprise game. Whatever the reason, the letters stayed in their vault and Roosevelt ended up winning the election by 5 million votes."

Kevin Drum at Mother Jones runs through past "October Surprises."