When characters on the same show take turns being the OnlySaneMan or StraightMan, but only one of them is sane at a time, that character is holding the Sanity Ball. Differs from the SmartBall in that the SmartBall gives a character the ability to problem-solve; the Sanity Ball gives its holder a rational perspective (and the knowledge that everyone around them is acting ''ir''rational).

Whenever the character holding the Sanity Ball gets a HeroicBSOD, or falls for LoveMakesYouCrazy, or gets PutOnABus, or otherwise loses the ball, someone else on the show picks up the Sanity Ball and runs with it, becoming the new OnlySaneMan.

Every faction has its own Sanity Ball, so the heroes may share one while the villains are sharing another.
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!!Examples:

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[[folder:Anime and Manga]]
* ''Manga/{{Beelzebub}}'' does have a few designated StraightMan characters, with Furuichi counting as the OnlySaneMan amongst a cast full of delinquents and demons. However even the CloudCuckooLander Oga comes out with bits of wisdom/cynicism if Furuichi decides to go off on one.
* Al and Leona in ''DominionTankPolice'' tend to trade off the Sanity Ball rather frequently.
* ''TheSlayers'': The Slayers' Sanity Ball is usually tossed back and forth between [[ObfuscatingStupidity Gourry]] and [[DeadpanSnarker Zelgadis]]. The secondary Sanity Ball is usually toted around by [[AffablyEvil Xellos]] (maybe that's what's on the end of his staff?), since he seems to be the [[OnlySaneMan Only Sane Villain]]. Usually.
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[[folder:Comic Books]]
* In ''ComicStrip/CalvinAndHobbes'', Hobbes generally carries the Sanity Ball when Calvin's interacting with him. On occasion, Hobbes's predator instincts/vanity/etc. take over and Calvin takes the ball. When Calvin interacts with adults, Calvin's usually the one with the ball. When he interacts with Susie, though, it's usually by chucking the Sanity Ball at her and running away.
** Calvin may hold the ball when his father is getting into one of his hobbies, but mostly the adults are a foil for his complete lack of common sense and some other qualities that don't exactly qualify him as the most sane character.
* In ''ComicBook/TheSandman - Brief Lives'', Delirium (the AnthropomorphicPersonification of madness) acts generally insane and wacky while her older brother Dream serves as her rational and pragmatic foil. After receiving some distressing news, however, he starts to lose it, and Delirium has to pick up the Sanity Ball, since "one of us has to keep this thing going". Later on when describing the event, she seems unable to remember anything beyond saying "It hurt..."
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[[folder:Film]]
* ''[[StarWars Return of the Jedi]]'': The Emperor turns psychotic at the end, and tosses the Sanity Ball to Darth Vader. Vader then gets the ball, has his first moment of sanity in a while, and [[HeelFaceTurn switches sides]].
* Characters in the ''AustinPowers'' films spend a lot of time passing the Sanity Ball around. For example, Scott Evil is usually the only sane man among the villains, but Number Two sometimes has sane moments as well.
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[[folder:Literature]]
* Happens a lot in ''Literature/{{Discworld}}'':
** The witches' coven has a Sanity Ball, usually (though not always) carried by Nanny Ogg.
** The wizards juggle two or three Sanity Balls, with the Librarian, Rincewind, Ridcully, and Ponder Stibbons being the most frequent holders. The Bursar ''had'' one at one point, but it's now considered too sharp to allow him to hold.
** The Watch's Sanity Ball is usually carried by Vimes, but he'll toss it to Carrot or someone else once in a while, as in the '''That! Is! Not! My! Cow!!''' incident.
** In Death's family, Susan or Death usually have the ball, but Albert takes it occasionally, such as when Death goes on vacation in ''Mort''.
** In the madhouse that is the political sphere of Ankh Morprok, the ball is usually in the firm grasp of Lord Vetinari. If you happen to hold it for a moment, it is because he dropped it at your feet. If you only ''think'' you have it, you will be proven wrong, often fatally wrong.
* In ''Literature/TheHitchhikersGuideToTheGalaxy'', Arthur starts off with the Sanity Ball, but he soon gets out of his depth. Ford Prefect carries the ball for most of the story, though Trillian/Tricia gets to hold onto it sometimes too.
** Considering that Ford is [[CloudCuckoolander still pretty out there]], this is saying something.
* Common in Creator/PGWodehouse's books. [[Literature/JeevesAndWooster Bertie Wooster]] is a semi-frequent recipient, sometimes borrowing it from [[TheJeeves Jeeves]] or otherwise sharing it with him.
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[[folder:Live Action TV]]
* ''{{Lost}}'': This happens a lot, especially between Jack and Locke, who seem to alternate between being the voice of reason and acting insane. Usually when Jack is acting crazy it's Locke who is the sane man, and the other way around when Locke is acting crazy. And for most of season five it was ''[[JerkWithAHeartOfGold Sawyer]]'' who had the sanity ball, oddly enough, as Jack had been relegated to second string and Locke was [[spoiler: NotHimself]].
* In ''Series/{{House}}'', Wilson or Cuddy both hold the sanity ball for House usually. This enables House's brilliance/insanity to counter his teams' mediocre/pragmatic approaches with the sanity ball holder to act as referee. But the ball is sometimes passed, to 13 (when Wilson is dealing with Amber's accident) and to House (when Cuddy is dealing with sick babies). House is reliably crazy when it comes to medical diagnostics but with regards to each team members individual problems (Cameron marrying chase, Foreman switching 13 off placebo, Taub confessing his affair, etc.) House has been sought for his reasonable opinion.
* ''Series/{{Farscape}}'': Early on, Crichton is the OnlySaneMan. As the series progresses, John becomes [[GollumMadeMeDoIt a bit less sane]], and Aeryn and even D'Argo are assigned occasional ball-carrying duties.
* Common on ''Series/ArrestedDevelopment'' - Michael holds it more often than anyone else, but promptly passes it to George Michael whenever he deals with the kids, and George Michael and Maeby play catch with it when they're together.
* Lampshaded in the ''{{Psych}}'' episode "Not Even Close...Encounters" when Gus and Shawn try to refrain from indulging in alien theories during their investigation:
-->'''Shawn''' (to Gus): Someone needs to hold the sanity bag in this partnership. And, frankly, I miss the days when it used to be you!
* In ''Series/DoctorWho'', the characters seem to be playing a constant game of hot potato with their Sanity Ball. Sometimes the Doctor, sometimes a companion, sometimes a companion's family member, currently, Rory seems to be holding it the most.
** Though Rory more often comes across as OnlySaneMan.
* ''{{Fringe}}'': Tossed around quite frequently, as everyone has a slightly different theory on where to draw the line between the very, very strange and the just plain impossible.
-->'''Peter''': So you're not buying that it's her husband's ghost?
-->'''Walter''': There's no such thing as ghosts.
-->'''Peter''': That's where you draw the line? Ghosts?
* Canadian teen sitcom ''Series/MrYoung'' passes this between Adam and Echo.
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[[folder:Webcomics]]
* The Sanity Ball is bounced around in ''[[http://www.jaydenandcrusader.com Jayden and Crusader]]'' a lot. Jayden started out with the ball acting as the straight man to Crusader, but eventually her anger issues and Zoiberg fetish made her pass the sanity ball to Crusader, who passes it off whenever he has something crazy to do. Third is arguably so sane he's crazy.
* In ''Webcomic/TheOrderOfTheStick'', a good dozen or so characters have passed the Sanity Ball around. Roy usually carries it, but when he was [[DeathIsCheap killed]], Haley and Durkon picked it up for their respective parties. Elan occasionally takes the ball for a bardic GenreSavvy moment.
* Used a lot in ''Webcomic/EightBitTheater''. Usually, both Thief and Black Mage can be relied on to be sane, but Thief will constantly behave irrationally as part of his own schemes, or Black Mage will go crazy and try to kill everyone. When these both happen at once, Red Mage will step in as the voice of reason, but usually his plans turn out to be even worse. But they tend to work anyway. And when the three of them are caught up in bickering and semantics, Fighter becomes the reasonable one, because he's too stupid to realize what's going on.
** Or, when they're ''all'' being crazy, White Mage.
* {{Webcomic/Homestuck}}: It's passed around in all the player's groups.
** The Pre-Scratch kids: Dave, inspite of his ramblings, is probably the best adjusted character, thinking rationally the most. Jade knows the most about the game, and John usually makes the most moral choices during the campaign. Rose plays the StraightMan the most often, and is the one who lays the plans for the alpha session, before giving up the ball when dealing with her issues becomes too much.
** The Post-Scratch Trolls: Kanaya and Karkat are the ones who focus most on the mission rather than be consumed with their personal issues.
** The Post-Scratch Kids: Dirk has the most reason, and plans to get them through the game. He's also the most rational. However, Roxy takes up the ball after she sobers up, and stays out of the love-triangle which messes up everyone, and her issues don't impede her anymore. When Trickster mode goes down, Dirk takes up the ball once again, having been unaffected by it.
** The Pre-Scratch Trolls: Rufioh and Porrim are the best adjusted, considering their teammates. Meenah is utterly irrational, yet she's the one trying to organize everyone to stop Lord English. Aranea was mixing both, being smart, and not focused too much on her talking obsession [[spoiler: but she renounces the ball following TheReveal of her plan.]]
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[[folder:Web Original]]
* Some of the characters in ''RedVsBlue'' tend to throw the Sanity Ball back and forth with each other, particularly Grif and Simmons, and also Church and Tucker.
* ''RoosterTeethShorts'': The Sanity Ball seems to be in the hands of someone different every episode. Most obvious with Joel, who tends to swing between being the Only Sane Man and being a complete Cloudcuckoolander.
** Matt is probably the most consistent with it, as even when he's "crazy", he's usually right or out-crazied by someone else.
* In ''WebVideo/YuGiOhTheAbridgedSeries'', the sanity ball is usually held by Yugi, but is passed around liberally; in recent episodes, even Tristan has held it.
* WebAnimation/HomestarRunner moves the sanity ball so much its hard to tell who's smarter than who. Out of the whole cast, Bubs, Strong Bad, Strong Sad, and Marzipan would probably be among the smarter members of the cast, but even then it changes. Marzipan can go from being the only sane person and ''within seconds'' become a complete lunatic. Even Strong Sad, who is usually depicted as the OnlySaneMan, has his moments of craziness. Note that "sane" is a relative term in this context, since Free Country USA is always {{Cloudcuckooland}}.
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[[folder:Western Animation]]
* ''StarWars: TheCloneWars''. Only a few clone troopers (from Hidden Enemy and Deserter) seem to realize that they are mostly used just to senselessly charge into battle and die.
* On ''JimmyTwoShoes'', either [[ThePollyanna Jimmy]] or [[EnfantTerrible Heloise]] hold the ball, depending on the joke. When interacting with Jimmy and Beezy, [[TheCaligula Lucius]] will occasionally hold.
* ''WesternAnimation/SpongebobSquarepants'': Spongebob tends to act like an actual ''adult'' whenever he and Patrick are the only characters on screen, if only to emphasize exactly how brain dead of a person Patrick really is. However, expect him to drop the Sanity Ball like a rock once [[OnlySaneMan Squidward]] gets involved.
** On the other hand, every now and then Squidward or another saner character such as Sandy will get a NotSoAboveItAll moment and cause a dilemma, usually with Spongebob acting as TheStraightMan. While this was more common in earlier seasons, this break in formula still occurs at times later on.
* ''WesternAnimation/InvaderZim'': Zim's robot GIR, dispite his processor being mostly made from trash and spare change, has occasional moments of clarity. The first would be when he question's Zim's plan to kill Dib in the past with time-travel, the second is when Zim decides to stop an explosion by undoing the timefield that's slowed it down.
** Dib can be manic and gullible or the [[DeadpanSnarker sarcastic]] OnlySaneMan, depending on the situation. The former is more common when he's talking to Gaz (who alternates a bit herself) while the latter usually occurs with Zim (who's almost always crazy).
* In ''WesternAnimation/MyLittlePonyFriendshipIsMagic'', Twilight Sparkle's relative level-headedness amongst her more outlandish friends usually lands her in the role of the [[OnlySaneMan Only Sane Mare]]. However, sometimes she can get carried away in her cynicism, and her SuperOCD makes her susceptible to stress-induced [[SanitySlippage mental breakdowns]], at which point the ball is, ironically, shared between her friends (most consistently, Spike).
** The show as a whole likes to evenly swap this around, with each character getting as many moments of clarity as they get flawed moments, depending on the circumstance. Even abrasive goofballs such as Pinkie Pie and Rainbow Dash sometimes prove more rational than the more lucid Fluttershy or Applejack.
* ''WesternAnimation/TaleSpin'' constantly trades the Sanity Ball around, most especially between Baloo and Rebecca. On average, both have an equal amount of idiotic or callous moments, usually with the other acting as TheStraightMan to it all.
* A common occurrence with Stan and Kyle in ''WesternAnimation/SouthPark''. While they CAN at times both play the StraightMan / OnlySaneMan in an episode, if one of them is in possession of the episode's IdiotBall, the other almost undoubtedly will play the sane one.
* Generally shared between [[CloserToEarth Leela]] and [[TheCloudCuckoolanderWasRight Fry]] in ''{{Futurama}}'', with a few rare exceptions.
** Lampshaded in ''Into the Wild Green Yonder'':
-->'''Amy''': Bender, are you crazy?
-->'''Bender''': Nah, it's Fry who's crazy in this one.
* On ''{{Spliced}}'', the ball gets passed around between Peri and Patricia mainly. Almost everyone except [[TheDitz Entree]] gets a turn with it however.
* Generally shared around rather evenly in ''ThomasTheTankEngine'', especially in later episodes, where most of the engines have spotlight concerning their flaws so even the most rational engine will sometimes need to be handed AnAesop by another sometimes more abrasive engine (eg. odd episodes [[SmallNameBigEgo James]] plays TheStraightMan to [[CoolOldGuy Toby]]). Thomas himself in particular fluctuates rather evenly between a reckless {{Keet}} or a kindly BigBrotherMentor.
* The Urpneys often swap the Sanity Ball around erratically in ''TheDreamstone'', ranging from the more [[MadScientist intelligent but sociopathic]] Urpgor, [[DrillSergeantNasty Sgt Blob's]] more focused but overzealous drill instructions, or [[SicklyNeuroticGeek Frizz's]] cowardly ([[GenreSavvy but rightfully so]]) desire to self preserve or [[CloudCuckooLander Nug's]] occasionally brilliant delusions. The heroes are less prone to this, though some do still have the odd fluctuation, especially [[AdorablyPrecociousChild Amberley]].
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