"Organized Psuedolegal Commercial Arguments" (or OPCAs) are a form of facetious arguments made by litigants and would-be political scholars that they are not under the rule or jurisdiction of law. The basic belief is that only certain forms of law are valid, either "natural law" or "contract law", and that by using a series of technicalities, a person can exempt themselves from answering to the legal system. The OPCAs are most popular in the English speaking world, and vary from country to country: some of them are specific to one country, such as the The Ohio argument against federal income taxes, while others such as the Freeman on the land arguments are based on ideas of "natural rights". There are a number of these theories, and there will probably be more oozing out of the woodwork of the internet. Rather than go into the history and details of all of them, I will encapsulate what they have in common.
Most of the arguments start from what is a valid philosophical question about the nature of legal authority. One of the basic ideas of the modern world is that society and government only exist through the consent of the governed, and the laws and governments are not absolute, abstract entities, but something that societies generate through an ongoing process of dialogue and reasoning. And it has been established in the 20th century that there is a duty of conscience, that sometimes people have to look beyond the stated laws to do what is right. Without Civil Disobedience the United States would have never had progress in civil rights.
So does the OPCA movement have a point? Are they post-modernistic defenders of the rights of the individual against the language games that are law and society? The problem is that they are not, and in fact are the opposite. Rather than being a critique of the series of legal entities and fictions that hold up the law, the OPCA advocates just seek to replace them with other entities and fictions. Rather than trying to further a rational dialogue about the rights of the individual versus the rights of society, OPCA replaces them with a different type of magic. Some of the major OPCA positions, for example, are that a court with a gold-fringed flag in it is not a real court or that children's "birth" certificate is really a "berth" certificate declaring them a ship. It goes on and on like this: most of OPCA comes down to saying "Nuh-uh! I had my fingers crossed". It is the type of rules lawyering that goes on when an eight year old is losing at Monopoly.
While I am sympathetic to the idea of people resisting the government out of conscience, and to the idea that society can be based on a more open social contract, the type of frivolous and silly arguments made by this school of thought are not doing anything for that cause.
A Canadian judge gives a rather expansive look at the OPCA movement:
http://ablawg.ca/2012/10/30/the-organized-pseudolegal-commercial-argument-opca-litigant-case/