If The Other Wiki is to be believed, then "Model United Nations (also Model UN or MUN) is an academic simulation of the United Nations that aims to educate participants about civics, effective communication, globalization and multilateral diplomacy." That is to say, it is supposed to be Exactly What It Says on the Tin.
This... is a simplification. What it really is, is LARPing in suits and being able to pass it off as an educational activity on your résumé/college applications. You might want to play Hearts of Iron with hard AI for a more comfortable experience.
Before we get into that, let's get into the theory: A high school, university or other organization says, "Let's have a Model UN conference!" What this means is that they will invest great (or not-so-great) quantities of cash into getting a venue, printing materials, and possibly snacks for "volunteers", and then call upon either high schools or universities to sign up and send students to the venue. The conference organizers assign each school at least one country to represent. At the actual conference, the organizers have thoughtfully created committees in which the students (called delegates) are supposed to discuss hot-topic international issues while role-playing a diplomat from one of the countries their school has been chosen to represent. Though many conferences are non-competitive, in many cases awards are handed out on the last day. May the best country win.
Before getting into too much detail, there are generally considered to be three types of committee: the General Assembly committees, which can be quite large (400+ delegates is common at large university-level conferences), and contain representatives of every UN country (so long as they have a school attached to them), slowly discussing some issue of general and long-term importance; specialized committees, which are rather smaller (generally no more than 50 people) discussing a rather more... well... specialized... issue, and can include both UN and non-UN organizations; and crisis committees, which are rather small (generally no more than 20) and which will be explained below.
In practice, things have gotten rather out of hand. It all started when conferences started simulating non-UN bodies, like the European Union or the League of Arab States. Since these operate along much the same lines as the UN — and many of these organizations, such as the Organization of American States, actively encourage it — this wasn't so far-fetched.
At about the same time, some actual LARPer or or Tabletop RPG player got in on the action and said "hey, wouldn't it be cool if we had the topic change constantly?" Conference organizers presumably had a test, and pronounced it good. The bizarre entity known as the crisis committee was born.
In this variant, a smaller committee (for instance, the 15-member United Nations Security Council) is given not a single topic to discuss, but several, emerging topics. Through clever use of fake intelligence reports, news articles, acting (generally either hamtastic or completely unbelievable) and (recently) video and audio recordings, a group of people (known as the crisis staff, but really a collective Game Master) tries to confuse the hell out of the participating delegates as they deal with a situation of... variable realism. Cue several crisis cabinets of varying insanity being created: Angola declaring war on the USA? The Soviet Union teaming up with space aliens to Take Over the World?note Anything goes in crisis committees, and it's a perpetual inside joke among MUN delegates when they're praised for "learning about world issues" when all they do in crisis committee is write a position paper and throw away country policy about the second they step in the door.
When this started with the Security Council, people started saying "Hey, I know! Let's start doing other things!" Like what, you ask? It started (as usual) logically enough, with things like NATO, the European Union, and other inter-governmental organizations. UN-like, and still diplomatic.
However, at some point, someone had the bright idea of simulating national cabinets. Again, government-related, educational, realistic. There might even be diplomacy involved. Getting off-track, perhaps, but not too off track... yet.
And then someone had another bright idea: start doing things in the past or the future. Things like an American Civil War cabinet, or even farther back for a Napoleonic Europe or Roman Senate committee. And then someone said, "screw politics, we're simulating Al Capone's mob! Or a corporate board of directors! Or something!." And then (in the last couple of years), someone said, "Screw the real world, we're simulating Star Wars! Or 24! Or The Lord of the Rings! Or Lost! Or Batman!!" This has gotten so out of hand that some conferences don't simulate the United Nations at all... they have become Model United Nations In Name Only. The delegates don't mind. At least not most of them.
Of course, much of this only applies to the collegiate level; high-schools still insist on having educational content, and most conferences have successfully avoided In Name Only. That said, it's grown quite far from its humble origins.
- Alternate History: Pretty much the name of the game in all historical committees. Since most of the historical committees deal with a famous historical war of some sort, delegates often get a chance to rewrite the history books, and the chairs tend to roll with it. Meaning that Stalin can team up with Japan in WWII and take over all of Asia, the South wins the Civil War, etc.
- Bollywood Nerd: A huge number of South Asians get involved in North American MUN for whatever reason, often leading to funny and awkward scenarios like having them represent the United Kingdom at a time when the UK owned all of their homelands, or have Indians play members of the Pakistani government (and vice versa).
- Boisterous Bruiser: Although the US always takes shit from everyone, it is usually more this trope than actively considered evil (with some exceptions; see below). As stated by Cracked, countries that don't consider the USA to be an enemy are more likely to slap the US on the back and say, "This guy! He might be a bit crazy, but you know, he's all right." (The real France and Britain are the most likely to have this reaction).
- Evil Feels Good: Some of the most-sought-after countries to represent are North Korea, China, Russia, Iran, Israel, Myanmar/Burma, Saudi Arabia, and the United States precisely because you can be a complete Jerkass and get away with it. To elaborate:
- North Korea is expected to be completely contrarian, obstructionist, and uncooperative;
- Russia and China have oodles of power and leaders devoted to Realpolitik, and can thus get away with anything they please;
- Myanmar and Saudi Arabia are exceptionally and openly authoritarian regimes (none of this People's Republic of Tyranny business for them: their motto is "damn straight we're a military dictatorship (Myanmar)/absolute monarchy (Saudi Arabia))". To be fair, Myanmar has recently become more of a hybrid regime than the outright junta it used to be, although the Tatmadaw (the official name of the Myanma armed forces) still more or less runs the show;
- Iran has been gaming the international system for three decades and holds positions diametrically opposed to most of the rest of the world (e.g. Iran can advocate nuclear proliferation, restricting women's rights, and call people infidels—and win);
- Israel's official policy is "we do what we need to survive, other consequences be damned," which more or less gives them a justification to be complete assholes to everyone if need be, including their own allies.
- The U.S. has tons of weight to throw around, which in some hands can compensate for a lack of subtlety or tact. The Bush administration (or facsimiles thereof) take this up to eleven; it's generally expected that MUN under the Trump Administration will see a return to this style of representation for the USA.
- Granted, none of this is evil (though many people regard some or all of these countries as such), but you're certainly the antagonist in the room... and that can feel pretty awesome.
- Fun with Acronyms: Most conference titles try to be acronyms. Many fail.
- Game Master: The crisis staff in crisis committees. The Chairperson of non-crisis committees can do a little bit of this, but is constrained by a theoretical commitment to noninterference.
- Good Is Boring: As noted above, many people love playing Axis of Evil type nations. Conversely, if you're roleplaying with any degree of accuracy, it can be awfully hard to find "fun" stuff to do with small pacifistic non-interventionist nations. It's hard to have a big angry "banging the shoe" speech when you're Belgium or Monaco or Kiribati. And truth be told, most of the "do-gooder" stuff the United Nations does in Real Life is ineffectual and/or boring. Any measure that passes is likely to be toothless and watered down (to appease whatever Great Power is actually doing the bad stuff, and doesn't actually want to stop.) Probably one reason why "crisis committees" held so much appeal for people who end up spending a weekend debating fisheries regulation in ECOSOC and the like. Nobody seems to like perfectly significant, but rather boring topics. Stolen cultural artifacts? Big problem in the developing world, but boring.note Unexploded ordinance? Huge problem in places like Laos or Cambodia that have had a lot of guerrilla conflicts in the recent past, but boring. A ridiculous World War Three scenario in which the Soviet Union teams up with alien invaders to Take Over the World? Yes please. War-related committees always go fast, high school, college, or otherwise. Good, peaceful topics are always the "oh man I got stuck with that one?" committee.
- Gorgeous Period Dress: Crisis staffs and chairs of crisis committees occasionally engage in this (or rather, what their budgets can afford), but it is strongly discouraged from delegates. It gets rather funny in Star Wars or Roman Senate as nobody takes it seriously anyway but dress code for delegates is still enforced.
- In Name Only: As noted above. Not for most things, though.
- Some delegates will be their country in name only; probably because they didn't look into their countries' foreign policy or stances on any of the issues to be discussed. Needless to say this becomes very annoying.
- On the other hand: FCMUN, Cho MUN (especially #XII): We're looking at you. Seriously, Harry Potter? The Mafia vs. Chicago Law Enforcement? And not even the dang Security Council to make things theoretically UN-ish? For shame!
- Just a Stupid Accent: Frequently, both by delegates (generally a) trying — and failing — to sound "authentic," b) for laughs, or c) to affect exoticness as an attractant for the opposite sex) and crisis staff (usually for laughs, often to distinguish multiple "characters" played by the same staffer, sometimes just because).
- Large Ham: A favored technique among certain delegates, as well as crisis staffs trying to evoke some of the more bombastic leaders (e.g. Hugo Chavez and Mahmoud Ahmedinejad).
- Off the Rails: A good delegate can thwart his/her chair/crisis staff's attempts at moving the debate/plot along to his/her advantage. Depending on whether or not the folks giving out awards are huge Jerk Asses, this either leaves said delegate with an award, smiling like a cat, or on the award-givers' shit list and coming back empty-handed.
- Played for Laughs: An effective delegate knows when to drop a joke or wry comment into a speech. A really effective delegate knows how to work MUN tropes and cliches into these jokes at exactly the right time, providing everyone—including the Chair—with much-needed relief.
- Player Archetypes: Exhibited in peculiar ways:
- The Roleplayer: Quite common. This delegate seeks above all else to conform to that country's policy. In more moderate forms, the roleplaying delegate will be very aware of the domestic politics of his/her country, and while not be crazy about it, never ever take any action that would take him/her "off policy." In extreme form, this delegate tries to channel the spirit of the country, too, very frequently hamming it up and making outrageous statements. The latter form is most common when the country is known to have extreme, unorthodox, or merely very strong opinions about something; delegates representing North Korea, Iran, and Venezuela are particularly prone to this sort of thing, as are ones representing Russia (given Vladimir Putin's status as a Memetic Badass and certified Magnificent Bastard). Delegates representing the US during George W. Bush Administration occasionally made use of extreme, hammy roleplaying, as well, and US delegates under the incipient Donald Trump Administration are probably justified in doing the same.
- The Munchkin: (also known as the Horace Mann kid) In MUN-speak, generally called a "gavel-hunter" (since the top prize in a committee is usually a gavel). The delegate who will do anything, anything to win an award, even if it means throwing policy out the window. The most likely to use Rules Lawyering *ahem* parliamentary maneuvering to ridiculous extremes. Many teams frown on this sort of behavior. Also notable for being the most likely to have a Pretentious Latin Motto.
- The Loonie: These are quite rare in the pure form, but towards the end of a conference, most delegates tend this way, with joke resolutions flying left and right, speeches completely unrelated to the conference becoming the rule of the day, and general madness and mayhem reigning. Joke prizes are often announced, and the Soviet Union or other empires might rise from the dead. North Korea may sing a song with the United States, or Iran might nuke the world into oblivion. In the World Health Organization. Or when China and Russia start holding an auction on the various states of the US.
- The Real Man: Impossible in most committees, as there is nothing to fight, and brawls on the committee floor are generally just not on (MUN is not the Mexican Congress, Verkhovna Rada or Taiwanese Parliament). However, both Roleplayers and Munchkins frequently adopt distinctly Real Mannish orientations in crisis committees that take the form of a war council or something similar, (why don't we just fight the enemy? is the usual question), depending on whether it would be true to the position (for the formernote ) or would make "victory" more likely for the latter.note
- Railroading: In crisis committees, generally done by the crisis staff. In non-crisis committees, Chairmen can do this, although this is extremely frowned upon. This frequently leads to...
- Rules Lawyering: A.k.a. parliamentary maneuvering. More common in large, slow-paced simulations (such as General Assembly committees), where it is seen as an annoying but perfectly realistic way of getting what one wants (usually blocking or delaying passage of an unwanted measure) Skill in rules lawyering is generally seen as a good thing in a delegate, and while it frequently annoys everyone at the time, good chairs generally recognize a job well done. That's right, rules lawyering is not only tolerated but rewarded; you see, Model UN committees being deliberative bodies, the Chair is not always right and always has to follow the rules. However, in small, fast-paced simulations (i.e. crisis committees), parliamentary maneuvering is generally frowned upon (except in the UN Security Council), because the delegates are usually supposed to be working together rather than fighting each other (again, except in the UN Security Council). Unfriendly amendments are used more to attempt to make a draft resolution unsupportable than to improve it. That may be just the United States, though, at that's what our Congress does.
- Serious Business: Debates can get quite heated. This is particularly true in high-level GA and Specialized committees at the university level, where the delegates are often specialists in the field and feel very strongly about the subject at hand. For instance any United Nations Environmental Programme at the university level is guaranteed to be loaded with a metric ton of environmental science and environmental policy majors, while ECOFINnote is bound to have a lot of economics, finance, and political economy students, the World Health Organization will be full of aspiring doctors, the Legal Committee (or even a full trial simulation, especially if it's the International Criminal Court or the International Court of Justice) full of aspiring lawyers, and the Commission on Narcotic Drugs will have a combination of sociology, psychology, and criminal justice students; and especially political science and international relations students will be pretty much everywhere. By the same token, any Specialized or Crisis committee with Africa or an African country as its focus will have a lot of African Studies and International Development majors, equivalent special committees will have specialists on that, and the United Nations Security Council and NATO frequently find themselves to be little meetings of self-described specialists in security studies and least one person in the room will have interned at NATO, the Pentagon, or something similar. Seriously, even in casual high school MU Ns the Security Council is almost certainly very hardcore.
- Zigzagged with historical, fictional or fantasy crisis committees: It can get very heated, but the fact that it is crisis driven is going to make it engaging and very fun if you participate properly.
- Wild Teen Party: Almost always follows a conference. Well, regularly at the college level. Sometimes there is an event every night. Usually, the big party is on the night before the half day final two and afternoon closing sessions. Some delegates just come FOR the parties.