* HeyItsThatGuy:
** In the original Los Angeles-based episodes of ''Mathnet'', the chief, Thad Green, was played by Creator/JamesEarlJones. Despite a change in chiefs with the move to New York City, Jones made one appearance via phone in a season 4 episode.
** The ''Mathnet'' segments in particular featured a number of notable cameos from people in the world of music, television and theater. [[WesternAnimation/TheSimpsons Yeardley]] [[Series/HermansHead Smith]], Music/WeirdAlYankovic, Marcia Wallace, and [[Series/{{Bewitched}} Dick Sargent]] and [[Series/{{MASH}} McLean Stevenson]] (as rivals in the same episode), just to name a few, all appeared.
** This also applied to people working off camera. First- and second-season writer David Yazbek later co-wrote the theme songs to ''Series/WhereInTheWorldIsCarmenSandiego'' and ''Series/WhereInTimeIsCarmenSandiego'' and also wrote songs for ''Series/BearInTheBigBlueHouse''. Pat Tuesday and George Frankly even appeared in a first-season episode of ''Where in the World..'', in which they gave out clues to the gumshoes to where the crook had gone.
** One of the regulars in the non-''Mathnet'' sketches, Reg E. Cathey, later turned up on ''Series/HouseOfCardsUS'' as restaurateur Freddy Hayes.
* HeyItsThatVoice:
** Gary Owens, alias the title character in ''WesternAnimation/RogerRamjet'', as Lt. Dirk Niblick of the Math Brigade. (Furthermore, like ''Roger Ramjet'', the Dirk Niblick segments were written by Jim Thurman and animated by Fred Crippen.)
** Jim Thurman as Glitch in the ''Mathman'' segments and as supporting characters in the Dirk Niblick segments.
* KeepCirculatingTheTapes: The series has not been rerun since the early 2000s, when it was rerun on Creator/{{Noggin}}, and there are currently no DVD releases planned. Domestic recordings do exist of many episodes, and they sometimes show up on Website/YouTube, but they are nowhere near exhaustive, and quality varies widely.
* SameLanguageDub:
** In "The Case of the Willing Parrot" from ''Mathnet'', the voice of Sunshine the Talking Parrot, who played as Little Louie, was provided by Jim Thurman.
** One of the shows' recurring sketches was "Grown-Ups". In the sketch, kids would talk about how they were going to need math in the future, but their voices were provided by adult celebrities, by the likes of Ed Koch, Lawrence Taylor, Marv Albert, Robin Leach, James Earl Jones, and Joan Rivers. This was done intentionally
** In "The Case of the Calpurnian Kugel Caper" from ''Mathnet'', in some shots, you are looking at Peggy Shay, and hearing her voice. But in other shots, you are looking at her, and hearing her same-language-dubbed-in-post-production voice, which was provided by Jon Devries. Again, this was done intentionally.
* TooSoon: An exception - not long after the September 11 attacks, Noggin aired an unedited episode in which George Frankly casually discussed having dinner at Windows on the World at the World Trade Center.
* WrittenInInfirmity: The likely reason Kate Monday is holed up in the "Mathnet" episode "The View from the Rear Terrace".
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