I was thinking of going with Syria/Lebanon, but instead: Richard Mourdock probably went from about a 65% chance of winning to about a 20% chance of winning. That's a pretty big deal -- every Senate seat matters.
The final debate didn't seem to have any effect on the polls, so in that sense it appears not to have mattered.
That's what I'll kick it off with, but what do you have? What do you think mattered this week?