Pipe Maze

Water pipes, ducts and similar things have a tendency to be arranged in ways that resemble great walls of metallic spaghetti.

This is especially common in Video Games that use thick pipes for Space-Filling Paths, Insurmountable Waist High Fences, or just generic platforms in an Absurdly Spacious Sewer or Eternal Engine.

Can sometimes be Truth in Television due to people taking the easy path out and just using whatever scrap parts they happened to have lying around.

Film

 * Parodied in the retro design of Terry Giliiam's Brazil, which had exposed ductwork everywhere. It even lampshaded the fact by having somebody advertise ducts on TV.
 * The Three Stooges
 * An underground area in The Goonies has one. Sloth pushes on a pipe and causes a traffic accident above.

Live-Action TV

 * The opening credits animation of the third series of Monty Python's Flying Circus.

MMORPGs

 * Found in City of Villains.

Tabletop Games

 * In Magic: The Gathering, the third sphere of Phyrexia is described as an "impenetrable tangle of metal pipes".

Video Games

 * Pipe Mania and its imitators - love 'em, love 'em so much. But if you're Scoring Points, you end up trying to get as many pieces filled as humanly possible, so you end up distinctly avoiding the straight route and trying for as many twists, turns, and go-back-throughs as possible. Bonus if you get a big square of 'em made out of two-ways rimmed by U-turns, so the water goes through the whole square once and then goes through it all one more time just to ensure you've covered enough territory.
 * Super Mario Bros 3 actually has a world called 'Pipe Land/Maze', which has quite a few levels which most probably come under this (aka, note the vast amount of pipes which don't do anything other than make temporary walls rather than actually taking anything anywhere) Although the background in the remake is even more completely insane in terms of pipe layout.
 * World 7-9 has a particular pipe maze level, though you don't travel through the pipes. A more straight example is World 7-1.
 * World 6-2 of the original Super Mario Bros also has an inordinate amount of pipes, many of which can be entered, implying that it may be the first attempt by the series. You don't travel through pipes in Mario Bros.
 * World 6-1 of Super Mario Bros 2.
 * New Super Mario Bros has levels 3-A and 7-A, and both even mimic the background layout of their SMB3 counterparts, only with updated graphics.
 * Stage 6 in Super Mario XP has a section filled with pipes and some of them are filled with red and green Piranha Plants.
 * Ratchet and Clank Up Your Arsenal has an (almost entirely optional) Absurdly Spacious Sewer section that fits this bill precisely. There are 98 "Sewer Crystals" to be found in this maze. It's hell if you're a completionist, as there's a skill point for getting all of them.
 * Sonic the Hedgehog 2 for the Game Gear/Master System, has the oddly named Scrambled Egg zone, which is basically a mass of pipes, and you have to very quickly choose ways to go sometimes. Often, you'll get it wrong and get flung into spikes. Trial and error at it's purest. Used slightly in Sonic Chaos's Electric Egg, and less so still in Triple Trouble's Atomic Destroyer, both with less cheap penalties.
 * Oh and Sonic Blast's Blue Marine zone, an icy underwater hell full of strong currents and pipes. You can breathe in the pipes, but that is almost the level's only saving grace. To say it is arduous doesn't even cover it.
 * You'll see one of these in Baldur's Gate II if you explore the Shadow Thief guildhouse proper. It's apparently used for training purposes.
 * Purple has you going through pipe systems on occasions, they are not mazes and are usually just there as a connection to Down the Drain.
 * In Bioshock you need to complete a Pipe Maze screen to hack vending machines and security systems.
 * Where's My Water, which takes place in a sewer system, has lots of pipes. Some of the levels invoke this trope, there's even a level named "Pipe Maze"!

Web Original

 * SCP Foundation's SCP-015, a mass of pipes and plumbing work that have taken over an entire warehouse.

Western Animation

 * The back areas in Monsters, Inc.. where Randall carries out his evil experiments are practically made of complicated plumbing. They even made custom software for creating the piping.
 * One episode of Futurama had an alien abduction of Fry happen via a needlessly complex tube similar to the famous screen-saver.

Real Life

 * Truth in Television: Visit a power plant sometime. The water/steam pipes really are arranged like this because all that stuff has to go somewhere.

Other

 * Pictured above, Windows XP shipped with a Pipe Maze generating screensaver. Windows 7, at least, does not.
 * Though the .scr file can be copied from Windows XP to Windows 7 for that retro feel. The more screens you have, the better the effect.