Discordianism is a modern, chaos-centered religion founded circa 1958–1959 by Malaclypse the Younger with the publication of its principal text, the Principia Discordia. It is widely regarded as a parody religion,

Founding
The very idea of a Discordian organization is something of an oxymoron. Nevertheless, some structure is indicated in Principia Discordia. The most general group, presumably including all Discordians (and potentially others), is The Discordian Society, whose definition is "The Discordian Society has no definition". Within the society are sects of Discordianism, each under the direction of an "Episkopos" (overseer in Greek, source of English bishop and episcopal).
Discordians who do not form their own sects, whether they belong to someone else's sect or not, make up the Legion of Dynamic Discord, and may be referred to as Legionnaires. Would-be Discordians are told in the Principia Discordia:
If you want in on the Discordian Society then declare yourself what you wish do what you like and tell us about it or if you prefer don't. There are no rules anywhere. The Goddess Prevails.

POEE
Some Episkoposes have a one-man cabal. Some work together. Some never do explain.
Episkopos are the Overseers of sects of Discordianism, who have presumably created their own sect of Discordianism. They speak to Eris through the use of their pineal gland. It is said in the Principia Discordia that Eris says different things to each listener. She may even say radically different things to each Episkopos but, all of what she says is equally her word (even if it contradicts another iteration of her word).

Episkopos
According to the Principia Discordia, a pope is "every single man, woman, and child on this Earth." Papacy, however, is not granted through possession of this card; it merely informs people that they are "a genuine and authorized Pope" of Discordia.
While the powers of a Pope are not enumerated in the Principia, we are given some idea from a note under the card which states, "A =POPE= is someone who is not under the authority of the authorities." Some Discordians have also taken it upon themselves to further elaborate upon the powers of a Pope. On the back of some Pope cards, the following message can be found:
The rights of a Pope include but are not necessarily limited to:
The third right (requiring permission from the deceased in cases of burying or marriage, but not baptism) may be a reference to The Church of Jesus Christ of Latter-day Saints practice of baptism for the dead, or it may just be a witty conflation of marriage and death. Being a Pope, it is arguably up to the reader to decide.
This understanding of the notion of Pope has far reaching consequences in Discordianism. For example, the introduction to Principia Discordia says, "Only a Pope may canonize a Saint. … So you can ordain yourself — and anyone or anything else — a Saint." The last enumerated right of a Pope may be an allusion to the necessary-and-proper clause.
A female version, with the word Mome substituted for Pope, has also been promulgated.

To invoke infallibility at any time, including retroactively.
To completely rework the Erisian church.
To baptise, bury, and marry (with the permission of the deceased in the latter two cases).
To ex-communicate, de-ex-communicate, re-ex-communicate, and de-re-ex-communicate (no backsies!) both his-/her-/it-/them-/your-/our-/His-/Her-/It-/Them-/Your-/Our-self/selves and others (if any).
To perform all rites and functions deemed inappropriate for a Pope of Discordia. Popes in Discordianism
There are as many interpretations of Discordianism as there are Discordians, and several definitions of Discordianism on the Internet center around the words "Ancient Greeks", "Chaos Worship" and "Anarchism". This is an extremely debatable assertion of what would define Discordian philosophy as a whole; indeed, it is a notion directly confronted by the concept of the Eristic Illusion, as mentioned in the following passage, a summary of part of the Discordian philosophy which appears in the Principia Discordia:
Here follows some psycho-metaphysics. If you are not hot for philosophy, best just to skip it. The Aneristic Principle is that of apparent order; the Eristic Principle is that of apparent disorder. Both order and disorder are man made concepts and are artificial divisions of pure chaos, which is a level deeper than is the level of distinction making.
With our concept making apparatus called "mind" we look at reality through the ideas-about-reality which our cultures give us. The ideas-about-reality are mistakenly labeled "reality" and unenlightened people are forever perplexed by the fact that other people, especially other cultures, see "reality" differently. It is only the ideas-about-reality which differ. Real (capital-T) True reality is a level deeper than is the level of concept.
We look at the world through windows on which have been drawn grids (concepts). Different philosophies use different grids. A culture is a group of people with rather similar grids. Through a window we view chaos, and relate it to the points on our grid, and thereby understand it. The order is in the grid. That is the Aneristic Principle.
Western philosophy is traditionally concerned with contrasting one grid with another grid, and amending grids in hopes of finding a perfect one that will account for all reality and will, hence, (say unenlightened westerners) be True. This is illusory; it is what we Erisians call the Aneristic Illusion. Some grids can be more useful than others, some more beautiful than others, some more pleasant than others, etc., but none can be more True than any other.
Disorder is simply unrelated information viewed through some particular grid. But, like "relation", no-relation is a concept. Male, like female, is an idea about sex. To say that male-ness is "absence of female-ness", or vice versa, is a matter of definition and metaphysically arbitrary. The artificial concept of no-relation is the Eristic Principle.
The belief that "order is true" and disorder is false or somehow wrong, is the Aneristic Illusion. To say the same of disorder, is the Eristic Illusion.
The point is that (little-t) truth is a matter of definition relative to the grid one is using at the moment, and that (capital-T) Truth, metaphysical reality, is irrelevant to grids entirely. Pick a grid, and through it some chaos appears ordered and some appears disordered. Pick another grid, and the same chaos will appear differently ordered and disordered.
Reality is the original Rorschach. Verily! So much for all that. – Malaclypse the Younger, Principia Discordia, Pages 00049–00050
And this from the Principia Discordia's very beginning, a Discordian koan:
Greater Poop: Is Eris true? Malaclypse the Younger: Everything is true. GP: Even false things? M2: Even false things are true. GP: How can that be? M2: I don't know man, I didn't do it.

Philosophy
The word Chao (pronounced similarly to "cow") was coined as the singular of chaos. In the Discordian religion the chao is a symbol of the 'pataphysical nature of reality; singular instances of chaos being at the center of pataphysical theory. The word is a pun that enables the following couplet in the Principia Discordia:
To diverse gods Do mortals bow; Holy Cow, and Wholly Chao.

Chao
The Sacred Chao is a symbol used by Discordians to illustrate the interrelatedness of order and disorder. It resembles a Taijitu (Yin-Yang) symbol, but according to the Principia Discordia:
The Sacred Chao is not the Yin-Yang of the Taoists. It is the Hodge-Podge of the Erisians. And, instead of a Podge spot on the Hodge side, it has a pentagon which symbolizes the Aneristic Principle, and instead of a Hodge spot on the Podge side, it depicts the Golden Apple of Discordia to symbolize the Eristic Principle.
The Sacred Chao symbolizes absolutely everything anyone need ever know about absolutely anything, and more! It even symbolizes everything not worth knowing, depicted by the empty space surrounding the Hodge-Podge. – Malaclypse the Younger, Principia Discordia, Page 00049
The choice of the pentagon as a symbol of the Aneristic Principle is partly related to The Pentagon in Washington, D.C., partly a nod to the Law of Fives, and partially for the Golden Ratio references associated with the pentagon/apple allegory. The Golden Apple of Discordia is the one from the story of The Original Snub (below).

The Sacred Chao
The Law of Fives is summarized in the Principia Discordia:
The Law of Fives states simply that: all things happen in fives, or are divisible by or are multiples of five, or are somehow directly or indirectly appropriate to 5. The Law of Fives is never wrong. – Malaclypse the Younger, Principia Discordia, Page 00016
The Law of Fives as quoted uses the word "Five" five times.
Like most of Discordianism, the Law of Fives appears on the surface to be either some sort of weird joke, or bizarre supernaturalism; but under this, it may help clarify the Discordian view of how the human mind works; Lord Omar is quoted later on the same page as having written, "I find the Law of Fives to be more and more manifest the harder I look."
Appendix Beth of Robert Shea's and Robert Anton Wilson's The Illuminatus! Trilogy considers some of the numerology of Discordianism, and the question of what would happen to the Law of Fives if everyone had six fingers on each hand. The authors suggest that the real Law of Fives may be that everything can be related to the number five if you try hard enough. Sometimes the steps required may be highly convoluted.
Another way of looking at the Law of Fives is as a symbol for the observation of reality changing that which is being observed in the observer's mind. Just as how when one looks for fives in reality, one finds them, so will one find conspiracies, ways to determine when the apocalypse will come, and so on and so forth when one decides to look for them. It cannot be wrong, because it proves itself reflexively when looked at through this lens.

The Law of Fives
The Original Snub is the Discordian name for the events preceding the Judgment of Paris, although more focus is put on the actions of Eris. Zeus believes that Eris is a troublemaker, so he does not invite her to Peleus and Thetis's wedding. This is "The Doctrine of the Original Snub".

The Original Snub
The Curse of Greyface is one of the most important parts of Discordianism. It features prominently on several pages of the Principia Discordia. According to the Principia, Greyface was a man who lived in the year 1166 BC and taught that life is serious and play is sin. The curse is a psychological and spiritual imbalance that results from these beliefs.

The Curse of Greyface
Greyface encouraged his followers to "Look at all the order around you" (Principia Discordia page 00042) and somehow convinced mankind to agree with his ideas about Serious Order. The Principia notes that it is something of a mystery why Greyface gained so many followers when anyone could have looked at all of the disorder in the world.
Greyface and his followers took the game of playing at life more seriously than they took life itself and were known even to destroy other living beings whose ways of life differed from their own. – Malaclypse the Younger, Principia Discordia Page 00042
For more details, see also the section "THE CURSE OF GREYFACE AND THE INTRODUCTION OF NEGATIVISM" in the fifth edition of Principia Discordia.

The Curse
By accepting that life is a serious, orderly matter, the followers of Greyface end up viewing things as either orderly or disorderly. In this system, order is preferred to disorder at all costs. This preference results in both constructive order and destructive order.
The alternative is to view things as either constructive or destructive. In this system, construction is preferred to destruction. Selecting construction results in both constructive order and constructive disorder.

Order/disorder and constructive/destructive
[M]ankind has […] been suffering from a psychological and spiritual imbalance. Imbalance causes frustration, and frustration causes fear. And fear makes for a bad trip. Man has been on a bad trip for a long time now. – Malaclypse the Younger, Principia Discordia Page 00042
The human race will begin solving it's [sic] problems on the day that it ceases taking itself so seriously. – Malaclypse the Younger, Principia Discordia page 00074
In addition to the generic advice of culturing your natural love of chaos and playing with Her, the Principia Discordia provides "The Turkey Curse Revealed by the Apostle Dr. Van Van Mojo" to counteract The Curse of Greyface. The Turkey Curse is designed to counteract destructive order. It derives its name from the fact that the incantation resembles the sounds of a turkey.

Counteracting the curse
The Principia Discordia contains the Law of Eristic Escalation. This law states that Imposition of Order = Escalation of Chaos. It elaborates on this point by saying that the more order imposed the longer it takes for the chaos to arise and the greater the chaos that arises. This can be read as an argument against zero tolerance and hard security, or just a statement about the world. It can also be seen as a parallel to the second law of thermodynamics.

Law of Eristic Escalation
The Pentabarf is the set of 5 holy laws of Discordianism. It is as follows:
The Pentabarf is the most fundamental of all Discordian catma. ("Catma" is a general term for Discordian teachings, sayings, quotations, explanations, jokes and illustrations, as distinguished from Discordian "dogma", which consists of certain specific passages from The Honest Book of Truth, cited in Principia.)
The 5th law mirrors both the nature of Taoist sayings ("the Tao that can be spoken of is not the true Tao"

There is no Goddess but Goddess and She is Your Goddess. There is no Erisian Movement but The Erisian Movement and it is The Erisian Movement. And every Golden Apple Corps is the beloved home of a Golden Worm.
A Discordian Shall Always use the Official Discordian Document Numbering System.
A Discordian is Required during his early Illumination to Go Off Alone & Partake Joyously of a Hot Dog on a Friday; this Devotive Ceremony to Remonstrate against the popular Paganisms of the Day: of Roman Catholic Christendom (no meat on Friday), of Judaism (no meat of Pork), of Hindic Peoples (no meat of Beef), of Buddhists (no meat of animal), and of Discordians (no Hot Dog Buns).
A Discordian shall Partake of No Hot Dog Buns, for Such was the Solace of Our Goddess when She was Confronted with The Original Snub.
A Discordian is Prohibited from Believing What he reads. The Pentabarf
In the Principia Discordia, "Five tons of flax" is given as the answer to the question, "Is there an essential meaning behind POEE?" (This is a reference to a Zen story about "Three pounds of flax.") Some discordians claim that the entire conversation between Greater Poop and Mal-2 (including "the three pounds of flax" story) is actually a collection of humorous koans.
Discordians have since taken "Five tons of flax" as an absurd slogan or as a universal answer to philosophical questions. "Flaxscript" is also depicted as a genuine form of scrip, serving to avoid the use of government-issued currency.

Five tons of Flax
"Consult your pineal gland" is a common saying in Discordianism. Although it has never been proven, the pineal gland is believed by some, such as Rick Strassman, to produce trace amounts of DMT (dimethyltryptamine), a psychedelic chemical which is believed to play a role in dreaming and other mystical states. It should also be noted that the pineal gland was also used in Descartes's explanation of Cartesian Dualism as the "seat of the soul" and the connection between the material and immaterial world. In some cases it is referred to as "the atrophied third eye". It has also been suggested that the third eye (Ajna) physically resides at this location between the two hemispheres of the brain.

The pineal gland
It is hard to describe Discordianism as a religion because Discordians do not have any specific beliefs or dogma that would set them apart from the practitioners of other religions. Many of the practicing discordians believe that humanity suffers from the "curse of Greyface" (i.e, takes itself too seriously) and thus needs to be saved from this grave outlook on life. Thus the discordians seek to reverse the "curse of Greyface" by teaching the people "to laugh at themselves and their problems/lives." This, the discordians believe, would solve most of the problems of the world. Discordianism is the only religion of the world where you are allowed to laugh at emperors and popes. (Most discordians recognize Emperor Norton I as their emperor and every person on this planet as a genuine pope as authorized by the apostles of Eris.)
While Discordianism is separate from modern neopaganism, a number of neopagans have incorporated elements of Discordianism into their beliefs. In addition, Neopagan author Margot Adler discussed Discordianism in her book, Drawing Down the Moon, while religious authority J. Gordon Melton lists Discordianism among various Neopagan groups in his Encyclopedia Of American Religions. (Melton claims to have excommunicated all other Discordians, based on the fact that he is a Discordian Pope. Being Popes themselves, they then de-excommunicated themselves and/or each other.)

Discordian-inspired works

Church of the SubGenius
The Illuminatus! Trilogy
Schrödinger's Cat trilogy
Surrealism
Zenarchy
Operation Mindfuck