David Letterman is a learned man, so when Rose Byrne put him on the spot with a spelling question, he turned the tables on her on 'Late Show' (Weeknights, 11:35P ET on CBS). Byrne is filming in Schenectady, New York, but after mentioning it, she asked Letterman if he could spell it.

He could and did. "You people in Schenectady can suck it!" he shouted in triumph. So he then put Byrne on the spot with a tricky city of his own: Indianapolis. Byrne has had higher education as well, but not being from the United States put her at a distinct disadvantage.

"I-N-D-I-A-N-A-P-O-L ..." She started off well, but then it all came apart around her.

First she tried "O" and then "A." Even Letterman pointing at his eye didn't help her out. "E," she said, and then after getting it, "I thought you meant like spelled like an eye."

Next time we have a feeling she won't be challenging him with any more impromptu spelling quizzes.