[[quoteright:350:[[WesternAnimation/TheSimpsons http://static.tvtropes.org/pmwiki/pub/images/mystery_box2.jpg]]]]
[[caption-width-right:350:The box! ''The box!'']]

->''"Now hold on, Lois! A boat's a boat, but the Mystery Box could be anything! It could even be a boat!"''
-->-- '''Peter Griffin''', ''WesternAnimation/FamilyGuy''

All right, contestant, you've made it to the final round of everyone's favorite GameShow ''[[Series/ThePriceIsRight The Trope Is Dope]]''. Now you have a choice to make between two fabulous prizes. The first is an all expense paid trip around the world, complete with a complimentary Rolls Royce and $5 million in cash. The second is... the Mystery Box! What's inside it? No one knows. It could be week-old garbage, or the keys to your new mansion. Maybe it's filled with rocks and mud, or maybe fabulous diamonds. It could be anything! Troper, make your choice!

[[folder:Game Shows]]
* ''Series/LetsMakeADeal'' is the TropeCodifier.
* This was also the premise of ''[[Series/TreasureHuntUS Treasure Hunt]]''.
* The UrExample may be ''Pick a Box'', one of the earliest shows on Australian TV. It started on radio in 1948, moved to television in 1957 and ran until 1971. The CatchPhrase of the program was "The money or the box?".
* ''Series/DealOrNoDeal'' has as many as 26. (Some European versions use boxes, but the original Dutch version, along with those playing FollowTheLeader on the U.S. version use briefcases instead)
** By the way, it's almost always mathematically sound to take the box rather than the deal.
* ''Series/SaleOfTheCentury'': Two examples on the Creator/{{NBC}}[=/=]syndicated run:
** "Instant Cash," where a contestant can, in exchange for the amount of his lead, take a 1-in-3 shot at selecting which box held a mini-cash jackpot (two had $100, the other $1,000 plus $1,000 per show until claimed).
** During the "Fame Game" segment, one card read "Mystery Money or Pick Again," where the contestant could take an unknown cash amount ($2 up to $2,000) or try to select another number. It later said "Mystery Money or Try Again" when the contestant could randomly pick a number by using their buzzer to choose (the number inside the lights that lit up when the buzzer was hit would be the choice).
* Truth in Game Shows, certainly. In the 1960s (and revived in TheNineties) there was a British show called ''Take Your Pick'', where the contestants had the option of taking either the prize money or the key to Box 13. Related to the MontyHallProblem.
* The titular BonusRound on ''Series/ShopTilYouDrop''. Presented with six mystery boxes, a team has 1:30 to open each and decide whether to keep the gift inside or exchange it for another gift at one of the stores in the mall. Exchanged gifts were only opened at the time of TheReveal while the total value of the prizes was added up; during the first two season (when the total to reach to win was $1,000 instead of $2,500), some of the boxes contained {{Zonk}}s that only added a few dollars to the team's total.
* In ''Series/ThePriceIsRight'' pricing game "1/2 Off", there are 16 boxes, one of which has $10,000 in cash. A player can remove half the empty boxes at a time if they can correctly determine if certain prizes are listed at full-price or half off, and narrow down to the box containing the cash.
* Russian game show ''What? Where? When?'' (adapted as ''Series/MillionDollarMindGame'' in the US) has these quite frequently. Usually, a team of six experts are given a description of what's inside the box, and they should guess what is it.
* Also from Russia, ''Pole chudes'' a sort-of remake/variation of ''Wheel Of Fortune'', does it the following way: if a player ends up on the "Prize" section of the wheel, he or she may choose to have a black box brought into the studio. Then the host gives an option to choose between the prize inside the box and an amount of money, which gets progressively bigger. The prizes in question are absolutely random, ranging from an automobile to (most notoriously) a head of cabbage. The player leaves the game after that. (He or she may opt to continue the game instead, though.)

[[folder:Film -- Live Action]]
* In Music/WeirdAlYankovic's ''Film/{{UHF}}'', there is a game show parody called ''Wheel of Fish''. The contestant wins a very tasty red snapper fish, but is given the choice to take a box. The contestant chooses the box and is mocked: "You took the box! Let's see what's in the box!" ... ''(box is opened; audience gasps)'' ... "NOTHING! Absolutely NOTHING! Stupid! You're so stupid!"

[[folder:Other Live Action TV]]
* At one point in ''Series/BoyMeetsWorld'', Eric tries to bribe some information out of a hotel desk clerk. The clerk refuses to divulge the information for "Mr. Washington" (a $1 bill) but says he might for "Mr. Franklin" (a $100 bill).
-->'''Eric:''' Mr. Franklin isn't here, but how about two Mr. Lincolns ''($5 bills)'' and ... a mystery bag! ''(pulls out small bag with a clown face on it and dangles it in front of the clerk)'' Maybe it's good. Maybe it's not.
* On ''Series/JustShootMe'', Nina wants a raise, and Jack offers her one... or what's inside the box. She takes the box, of course, which only has a picture of an ugly baby inside (it's one of Maya's baby photos).
* Parodied regularly on ''Series/TheLateLateShow''. Craig will ''imagine'' a box, [[InsaneTrollLogic the contents of which he somehow does not know, and ask the guest to guess what's in it]]. They always guess "correctly."
* Inverted in several cooking shows, most notably ''Series/{{Chopped}}''. The mystery boxes are what contestants compete ''with'', as they contain ingredients (and occasionally other instructions.)

[[folder:Video Games]]
* Found in, of all places, ''VideoGame/CallOfDutyWorldAtWar'' when playing Nazi Zombies. Using your points to open a box instead of purchasing a gun is a bit of a crapshoot. You may end up with a sniper rifle (which is horrible to fight zombies with at close range) or the all powerful Ray Gun.
* ''VideoGame/TeamFortress2'' has the "Mann Co. Supply Crate" that randomly drops along with everything else. To open it you need to buy a key from the ingame store for $2.50USD. These crates can contain commonly dropped weapons (enjoy your $2 Equalizer), paint to recolour your hats or a special hat that has a particle effect applied to it. These hats have a <1% chance of actually being in a crate.
** The crates became more valued with the introduction of "Strange" weapons that [[BodyCountCompetition count your kills]]. Now, all weapons obtained from crates, with the exception of certain holiday crates, are Strange, making the deal a bit more fair. Those particle effect hats are still ridiculously rare, though.
* Be careful when opening a "mysterious present" in ''VideoGame/KingdomOfLoathing''; it might contain a random gift item, but it also might contain a boxing glove on a spring, which will punch you for severe damage if you open the box.
* Players that bought a lifetime subscription in ''VideoGame/TheSecretWorld'' can give up their subscriber benefits for a month for a Mystery Box that contains either nothing, a pitiful amount of in-game money, or rare and powerful endgame items.
* This was actually the mechanic for the game ''VideoGame/ToeJamAndEarl''. Players would start off with a random assortment of presents. Trial and error (and bribery) was the only way to discover what was in each type of box, which could just as easily have a helpful item or a free life as spawn an Earthling or bring instant death. Of course all your hard work went out the window if you managed to hit a Randomizer.

[[folder:Web Animation]]
* When ''WebAnimation/BarbieLifeInTheDreamhouse'' has Skipper host the game show ''I'm Barbie's BFF!'', she begins the final round by asking if any of the contestants would like to open Door #3. Raquelle refuses, recalling how many other game shows have lame consolation prizes. [[spoiler: It later turns out Door #3 had Ken behind it, leaving Raquelle frustrated on how close she came to taking him away from Barbie.]]

[[folder:Western Animation]]
* In ''WesternAnimation/TheSimpsons'', Mr. Burns pulls this out when trying to bribe some nuclear safety inspectors.
-->'''Mr. Burns:''' You can either have the washer and dryer where the lovely Smithers is standing. Or you can trade it all in ''(pulls out a box with question marks all over it)'' for what's in this box.\\
'''Inspector:''' The box! The box!
* In ''WesternAnimation/FamilyGuy'', Peter's offered the chance to get a free boat, but he decides to take the Mystery Box instead, which merely contains tickets to a stand-up comedy show.
-->'''Peter:''' A boat's a boat, but a mystery box could be anything! It could even be a boat! And you know how much I've wanted one of those!\\
'''Lois:''' Then let's just...\\
'''Peter:''' [[WhatAnIdiot We'll take the box.]]
* In one ''WesternAnimation/LooneyTunes'' cartoon, Daffy Duck turns down the "million box" which has a million smaller boxes inside it... and once Bugs gets the box, it's revealed that each tiny box had a dollar bill inside.
* In the first episode of ''WesternAnimation/The13GhostsOfScoobyDoo'', Shaggy and Scooby are offered their choice of a fancy doghouse, the airplane in which they arrived or the Mystery Box. The last is actually the Chest of Demons; when opened, it releases the 13 demons that had been trapped inside.
* ''WesternAnimation/TheJetsons'' and the Spacelys entered a game show and the Jetsons won. George then had a choice: collect the Grand Prize or whatever was behind the force field. If he picked the force field, Mr. Spacely would get the Grand Prize. Fearing for his job, George chose the prize hidden behind the force field. The force field then revealed a new stove (it was earlier shown to the viewers that the Jetsons needed one) and Mr. Spacely got a set of [[TheRival Cogswell]] products.
* [[ComicStrip/USAcres Roy Rooster]] won 1 ''[[EleventyZillion skillion]]'' dollars, a mansion with two kidney-shaped pools (to be anatomically correct) and several other prizes but traded everything for whatever was behind curtain number three. He got a dirty sock. The host commented that he's been on it for years and never gave any money but got rid of several socks already. The story started with Roy chasing the end of a rainbow to get a pot of gold but the leprechaun he met there said he no longer had it so he instead gave Roy a dirty sock and a chance to trade it for whatever was behind curtain number one. He got a car and was allowed to trade it for whatever was behind curtain number two and that's how Roy won the prizes he traded for whatever was behind curtain number three.
* ''WesternAnimation/{{Animaniacs}}'': Slappy Squirrel once left a can at somebody else's garbage bin. The owner didn't like this and the two of them fought to pass it over to each other. One of Slappy's moves was having her rival trade prizes for whatever was behind a curtain. [[spoiler:It was the can]].
* WesternAnimation/{{SpongeBob|SquarePants}} and Patrick once tag teamed in a wrestle match and won. They could choose the money or whatever was behind the curtain. The trope was averted because, in that case, the winners were allowed to know what the prize behind the curtain was before they made their choice. Their option was trading the money prize for a trip to a wrestling-themed camp. Much to [[TheScrooge Mr. Krabs']] dismay, they chose the camp.
* ''WesternAnimation/TheMrMenShow'' had the episode "Game Shows." In the first segment in that episode, there was a game show entitled ''[[ExactlyWhatItSaysOnTheTin Guess What's in the Box]]'', hosted by Mr. Nosy and Mr. Small.
-->'''Mr. Small''': The rules are simple. We'll show you a box, and you must guess what's inside.
-->'''Mr. Nosy''': Answer correctly, and you'll win whatever's in the box!
** The contestants were Mr. Rude, Miss Chatterbox, and Mr. Grumpy. Guess who won, and what was in the box; Miss Chatterbox, who ended up winning a [[{{Zonk}} donkey]].

[[folder:Real Life]]
* [[http://en.wikipedia.org/wiki/Newcomb%27s_paradox Newcomb's Paradox]] is a thought experiment in which you are presented with Box A, known to contain $1,000 and Box B, which may contain nothing or $1,000,000. Your options are to take both boxes, or only Box B. The twist: the person running the game can [[TheOmniscient reliably]] [[{{Seers}} predict]] [[RetroactivePrecognition the future]]. If he predicted that you'd take both boxes, he left Box B empty; if he predicted that you'd take only Box B, he loaded it with the million-dollar payoff. What do you do?
** The apparently ironclad argument for taking both boxes: It's too late for the game-runner to change the contents of the boxes, so taking Box A gives you an extra $1000 no matter what.
** The apparently ironclad argument for taking only Box B: The game-runner has a good record at prediction, so taking only Box B makes it very likely that you'll get the million.

->You're gonna choose the box, aren't you? ''(chuckles)'' [[SchmuckBait Sucker]].