David Michael Letterman (born April 12, 1947) is an American television host, comedian, writer, and producer. He hosted a late night television talk show for 33 years, beginning with the February 1, 1982, debut of Late Night with David Letterman on NBC, and ending with the May 20, 2015, broadcast of Late Show with David Letterman on CBS. In total, Letterman hosted 6,028 episodes of Late Night and Late Show, surpassing friend and mentor Johnny Carson as the longest-serving late night talk show host in American television history. In 1996 Letterman was ranked 45th on TV Guide's 50 Greatest TV Stars of All Time.

NBC kept Letterman under contract to try him in a different time slot. Late Night with David Letterman debuted February 1, 1982; the first guest on the first show was Bill Murray. Murray later went on to become one of Letterman's most recurrent guests, guesting on the show's 30th anniversary episode, which aired January 31, 2012 and on the very last show, which aired May 20, 2015. The show ran Monday through Thursday at 12:30 a.m. Eastern Time, immediately following The Tonight Show Starring Johnny Carson (a Friday night broadcast was added in June 1987). It was seen as being edgy and unpredictable, and soon developed a cult following (particularly among college students). Letterman's reputation as an acerbic interviewer was borne out in verbal sparring matches with Cher (who even called him an asshole on the show), Shirley MacLaine, Charles Grodin, and Madonna. The show also featured comedy segments and running characters, in a style heavily influenced by the 1950s and 1960s programs of Steve Allen.  The show often featured quirky, genre-mocking regular features, including "Stupid Pet Tricks" (which had its origins on Letterman's morning show), Stupid Human Tricks, dropping various objects off the roof of a five-story building, demonstrations of unorthodox clothing (such as suits made of Alka-Seltzer, Velcro and suet), a recurring Top 10 list, the Monkey-Cam (and the Audience Cam), a facetious letter-answering segment, several "Film[s] by My Dog Bob" in which a camera was mounted on Letterman's own dog (often with comic results) and Small Town News, all of which would eventually move with Letterman to CBS.  Other memorable moments included Letterman using a bullhorn to interrupt a live interview on The Today Show, announcing that he was the NBC News president and that he was not wearing any pants; walking across the hall to Studio 6B, at the time the news studio for WNBC-TV, and interrupting Al Roker's weather segments during Live at Five; and staging "elevator races", complete with commentary by NBC Sports' Bob Costas. In one infamous appearance, in 1982, Andy Kaufman (who was already wearing a neck brace) appeared with professional wrestler Jerry Lawler, who slapped and knocked the comedian to the ground (though Lawler and Kaufman's friend Bob Zmuda later revealed that the event was staged).

Did anything significant happen on the show?
Letterman using a bullhorn to interrupt a live interview on The Today Show,