This is a must-watch video, recorded from at least three different angles. (From a John McCain media availability in Panama City, FL held on Friday, August 1, 2008.)

Update (10:40AM): Several folks have asked to see what his eventual response was. C&L has posted it here. Short version: he seemed to snap back completely, and hit on his talking points, even distorting his record of fighting against a holiday for MLK.

Update 2 (12:49PM): If you're trying to digg this page, don't bother -- the pro-McCain bury brigade has buried it.

Update 3 (1:34PM): By request, I've uploaded a new clip with the beginning of his answer to the question and embedded it on this page. You can view the original here. (The only difference is that the beginning of his answer to the question is in this new clip.)