Letterman is the great example of this, although you could also look at Seinfeld, or Conan O'Brien.
Memento, World Wide Web
Modernism: move from impressionism (expressing human emotion) to cubism (showing multiple sides of something), to various forms of absurdity and art that drew on the unconscious (dada, surrealism), to more formal work (e.g., Kandinsky), to colour fields (Rothko) and drip painting (Pollock). In all this there was a progressive move away from actual objects, and toward that which drew them together, whether that was the interior "spirit", or the exterior "form".
Postmodernism moves away from the abstractions or universals, and away from the humanism that it implied. Andy Warhol, for instance, represents an important move toward the everyday, particularly the world of marketable images. Roy Lichtenstein paints comic panels - another celebration of the mundane and popular, instead of the "high".
The modern claims to give us a window on "true" reality, or the way things really are. The postmodern does not believe that is possible, but rather holds that all our ways of understanding the world are really constructions. Example: Pompidieu Centre, Paris
Modernity claimed to give us "deep" meaning. Postmodernity claims only to give us connections between things.
Examples: Disneyworld, West Edmonton Mall