CBS's Late Show with David Letterman regularly featured different sketches which followed the monologue and preceded interviews with guests. Often they were repeated absurdist segments involving various cast members, Letterman's friends, audience participation, edited or contrived news or promotional videos, or competitions and stunts staged outside the Ed Sullivan Theater in Manhattan, New York. Many of the same sketches originally debuted on Letterman's two previous series, NBC's Late Night with David Letterman and The David Letterman Show.

The show's regularly scheduled segments consisted of "Small Town News" on Mondays and "Fun Facts" on Fridays. Thursdays often featured a rotating set of three audience participation segments: "Know Your Current Events", "Stump the Band", and "Audience Show and Tell." "Stupid Pet Tricks" and "Stupid Human Tricks", two of Letterman's trademark bits from Late Night, continued to be presented on the Late Show, although much less frequently.

There were also running gags which often continued for about a month like playing José Feliciano's "Old Turkey Buzzard" or other sound effects when a card "crashes through the window", telephone calls from "Len Easton, California Highway Patrol", or Joe McCain on a telephone which Letterman acknowledges is a prop that is not connected. Letterman expresses amusement or annoyance during these recurring events.

These are sketches which have been featured on the Late Show with David Letterman.

Kalter introduction Announcer Alan Kalter's (and before him, Bill Wendell's) introduction of Letterman, while technically not a skit, assigned a bizarre modification to Letterman's name and appears at the beginning of every show. ("And now: Microscopic Sea Creature, David Letterman!") Letterman's title changes every night and often makes reference to a current event. ("And now: Disenfranchised French Youth, David Letterman!")

Prior to September 11, 2001, the first line of Wendell's and Kalter's introductions contained humorous descriptions of New York City ("From New York! Where the rats hate the subways, too!"). Once the Late Show returned to air on September 17, 2001, the introduction changed simply to, "From New York! The greatest city in the world!" That remained the standard introduction for over ten years; however, "The greatest city in the world!" is omitted from episodes with guest hosts, as is the host 'title'. In 2011, Kalter took to shortening 'David' to 'Dave' in his introduction of Letterman. At some point prior to late 2012, he once again returned to using 'David'. Beginning on January 2, 2013, the introduction began "From the heart of Broadway, broadcasting across the nation and around the world!", while Kalter also included a brief self-introduction of himself ("I'm Alan Kalter") after introducing Paul Shaffer & The CBS Orchestra.

Sketch participants While Letterman himself often participated in many of the show's non-"desk comedy" routines in its earlier years (as well as on Late Night), over time he increasingly preferred to have others star in them instead. Later he was rarely featured in any of the show's frequent pre-taped bits. Kalter, bandleader and sidekick Paul Shaffer, and Hello Deli proprietor Rupert Jee were often used instead in comedy routines, as was stage manager Biff Henderson, stagehands Pat Farmer and Kenny Sheehan, handyman George Clarke, "cue card boy" Tony Mendez, head carpenter Harold Larkin, cameraman Dave Dorsett, assistant Stephanie Birkitt, former writers Gerard Mulligan and Chris Elliott (who almost always appeared together), and Johnny Dark (a personal comedy friend of Letterman's).

Letterman's mother, Dorothy, also made appearances (via satellite from Indianapolis) from time to time including each Thanksgiving. Perhaps her rise to fame was mostly as a result of her nightly reporting from the 1994 Winter Olympics in Lillehammer, Norway.

Former recurring players from the show included Mujibur Rahman and Sirajul Islam (employees of a nearby gift store which moved once prior to Rahman and Islam appearing for a last appearance in January 2003) Their business closed a decade after they debuted on Letterman's show. Other people who appeared in sketches were Calvert DeForest (a.k.a. Larry "Bud" Melman), and scenic designer Kathleen Ankers (reprising her Late Night role of "Peggy, the Foulmouthed Chambermaid"; on CBS, she was the equally censored "Helen, the Ill-tempered Ticket Lady").

Random cameo appearances were made during the span of the show, most notably in the earlier years by Tony Randall, with Regis Philbin later filling that void. For a while, Letterman took great delight in making fun of his employer, continuing a tradition established at NBC, with senior CBS Corporation executive Les Moonves often serving as the target of his ire. In time, Letterman's relationship with Moonves improved; a segment titled "More with Les" featured jocular phone calls between Letterman and Moonves.

Alan Kalter Announcer Alan Kalter was frequently used in comedy bits, often with Kalter being the butt of the joke:

Kalter the Pervert In some skits, Kalter is portrayed as a deluded sexual deviant, often referring to himself as "Big Red." Letterman frequently followed them up by jokingly commenting to Shaffer on Kalter's disturbing, sickening nature, while Kalter grins mischievously. Often such skits began with Letterman informing the audience that Kalter had approached Letterman prior to the show (about which Letterman often adds, "I've asked him not to do that"), and explaining that Kalter had asked to comment on a current news or pop cultural event.

Kalter then begins a monologue where he speaks directly to the camera, setting up the nature of the topic (often the separation of a public couple) in a serious manner. He then addresses a separate, closer camera in a sexually provocative manner as amorous music plays in the background. The material is often a series of double entendres, with Kalter offering to romantically console the woman who is the center of the problem and ends with him making passionate moans. A disturbed Letterman then interrupts Kalter and chides him for behaving inappropriately. Kalter often ends the bit by making a provocative quip to Letterman and then rips off his headset and exits the stage in a "huff."

Kalterworld Occasionally, Kalter used his segments to promote "Kalterworld", a supposed web site selling "the finest in adult toys, games, and novelties." The Kalterworld.com url leads to the official Late Show web site.

"Alan Kalter Makes Your Product Sound Sexy" Kalter promotes an actual commercial product (for example Ajax) in a provocative and suggestive manner. He then pours the product on his head and smears it on his body, often moaning as he does so and then screaming in pain as it gets into his eyes. A bland voice-over then encourages companies to participate in the segment by submitting their own product to a particular address.

Kalter the Singer Kalter is introduced with the implication that he will provide a serious commentary on current events, but instead exuberantly sings a contemporary pop song filled with sexual innuendos (often from the female perspective). Songs included "My Humps" on "Alan Kalter's Political Roundup", "Don't Cha" on "Alan Kalter's Mideast Update" and "London Bridge." As he performs, Kalter struts across the stage with a disturbed and annoyed Letterman visible at his desk finally exiting at the other side.

Kalter Gets Maimed The show will often employ bits where severe bodily harm is supposedly inflicted on Kalter (such as when a cocktail waitress walks across the stage in Kalter's direction and then tosses the drink into his face). He then writhes on the ground groaning and acting as if in serious pain. A wry Letterman will sometimes advise an inattentive Kalter to use a medication normally used for more mild injuries including Neosporin or Ibuprofen.

The Guy Who Beats Up Alan In one recurring gag, Kalter makes a statement on a particular topic, only to have a large man appear from nowhere and object to Kalter's comments. He then proceeds to pummel him, which results in Kalter rolling on the ground in agony, and storms off backstage. Letterman will often amusedly ridicule the obviously fake nature of the violence, as the man's blows never come anywhere near Kalter, despite Kalter's best efforts to sell his pain. ("That last punch came at least within a foot.")

Later the beatings were followed up by pre-taped pieces, in which the relationship between Alan and the man who beats him (identified as "Brian") was shown to be more complicated. One sketch involved Kalter catching Brian being "unfaithful" by beating up another man on the street, and the two being heartbroken by the event. Another followed Brian punching Kalter in the face despite his "Not (in) the face!" pleas. After Brian storms off backstage, a video shows Brian expressing guilt to his wife or girlfriend about his abuse towards Kalter, fearing it was "pushing him away." The two later make up at the end with Brian meeting Kalter and punching him in the stomach instead of the face, much to Kalter's happiness. The videos are presented in a mock romance-drama style, with a soundtrack of emotional pop songs.

"TV's Uncle Jerry" In 2006, Kalter began to introduce himself by saying "I'm Alan Kalter, TV's Uncle Jerry", much to Letterman's delight at first, but over time Letterman regarded the moniker with faux-irritation, which appeared to be part of the joke. In August of the same year, several weeks after the bit started, the Late Show aired a clip from a new, fake CBS domestic sitcom entitled "Oh, Brother!" where Kalter played the aforementioned "Uncle Jerry" character. In the clip, Jerry abandons babysitting his brother's children on his wedding anniversary to instead join a friend at a bar who had met two flight attendants. He then uses a would-be catch-phrase: "Hey, Uncle Jerry's gonna get busy!" Despite introducing the clip with some enthusiasm, Letterman quickly dismissed it afterwards, saying "That sucked! That just sucked!" Kalter took to introducing himself as other beloved television characters including TV's Professor Withers, TV's Johnny Mambo, and TV's Uptown Ricky Brown. He has also introduced himself as "TV's Howie Mandel", to which Letterman said that made no sense at all.

"Alan Kalter's Campaign Roundup" A near-daily running gag presented late in the 2000 presidential election season began with Letterman introducing Kalter, who would ostensibly give a summary of the latest campaign news. Instead, Kalter would perform an energetic rendition of the chorus to "Who Let the Dogs Out?" which was a popular and ubiquitous song at the time and walk across the stage. In the skit's later occurrences, Kalter sometimes ripped off his shirt while he sang (revealing a pale and flabby physique) and adding a manic and deranged tone to his performance. Kalter has demonstrated a compulsion to disrobe in many of his other segments.

Alan Punches Someone Out In another long-running gag, Kalter would have a problem with something said at his expense, such as a Top Ten List entry, or a letter read during the "CBS Mailbag" segment. Kalter pressed Letterman about the statement, asking "Did he really say that?" and Letterman would confirm its accuracy. Kalter would then leave the stage to hunt down the person who said it, usually higher up in the building in the Late Show offices. During his transit, an individual would often greet Kalter with "Hi, Alan!" only to be ignored. After finding the guilty party, Kalter would then punch him out and walk away with a look of satisfaction. In one instance, the person on the receiving end was Regis Philbin, who had just been shown in a "Who Wants to Be a Millionaire?" clip where a question described Kalter as "creepy."

Alan Kalter's Celebrity Interview