If you've enjoyed the last three years of David Letterman's "Great Moments in Presidential Speeches" -- a nightly sound bite from our blunder-in-chief that's probably done as much if not more to succinctly calculate the president's IQ than even "The Daily Show" -- the final segment will appear tomorrow night on "The Late Show With David Letterman." In fact, the segment exits via a three-minute collection of the best moments. Here's a lil' preview ...

Letterman's on CBS (WBBM-Channel 2) at 10:35 p.m.