Mets starting pitcher R.A. Dickey has been one of the best stories during the first half of the season. He just made his first appearance in an All-Star Game at the age of 37 and he's made the knuckleball cool again.

And now, Dickey's been on Letterman. Below is the clip, which culminates in Dickey throwing a few knuckleballs to David Letterman.

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