It was one of the highlights of the 2008 presidential campaign and a role that earned Fey an Emmy for Outstanding Guest Actress in a Comedy Series in 2009. Fey also parodied Palin's one-on-one interview with CBS news anchor Katie Couric and Palin's performance in the vice presidential debate against Joe Biden.
Letterman isn't the only one making the Fey/Palin/O'Donnell comparison. Stick a pair of glasses on O'Donnell, and well, the result is rather uncanny. Check out The Examiner's gallery of Palin and O'Donnell side by side.