That was former New York Giants running back Tiki Barber, now an NBC Sports commentator, talking to Jenna Wolfe and Brian Williams. Wolfe made a joke about Barber not having a Super Bowl ring, and a short time later, after Williams made a comment about the Olympic "medal count," Barber said what sounded to some like the C-word, perhaps insulting Wolfe after he felt that she had insulted him. (A poll at popeater.com shows 56% of respondents saying that Barber said the C-word.)
I'm not totally sure what Barber said, although I'm going to give him the benefit of the doubt and say he was just repeating Williams' "medal count" and slipped up a little bit.
More at Awful Announcing and Pro Football Talk.