text: When he threw his pencils through the fake window scene behind him, a sound effect of breaking glass was always heard. Occasionally, if sound effects technician Howard Vinitisky was slow in triggering the appropriate breaking glass sound effect, Letterman would mockingly chide Vinitisky for the error (he would also occasionally congratulate Vinitisky when the sound effect was especially well-timed).
  A robotic arm for a while delivered the Top Ten List, and for another week or so, a complicated series of tubes would produce swirling coffee to eventually land in his cup on the desk.
  Cameras mounted on a chimpanzee's back (Late Night Monkey Cam) or on the roof (Roof Cam) would show odd viewpoints of the set and its participants.
  Other show format innovations related to the way individual episodes or segments were presented:
  The Custom Made Shows allowed the audience to vote on each part of the hour, what they wanted to see, and the resulting shows had guests talking in high-pitched voices like they had inhaled helium (Jane Pauley refused to say a word during this, and answered his questions by writing answers on cards and showing them), sitting in dentist chairs or lawn furniture, the theme music replaced by the theme from Gilligan's Island, and an opening montage of the director's vacation photos.
  Reruns were often scoffed at by Letterman, telling the audience not to waste their time watching next Monday.  Sometimes the entire rerun would be dubbed into a foreign language for rebroadcast, baffling viewers.