!Kung* is technically the name of a language group used by some San. It is often used as a name for the people themselves. They are a network of (formerly) nomadic hunter-gatherers who live in the Kalahari Desert of Africa. They are famous in anthropological circles because they were one of the few hunting and gathering societies left uncontaminated by westerners. They are also of interest because they have an egalitarian society, and because they are members of a racial group called the khoi-san.
They are also famous, at least in America, because they were the subject of the movie The Gods Must Be Crazy.
They are also called the San, Sonqua, Kung, Ju/'hoansi, Bosjemans, Hottentots, and Bushmen. (Those last three are not PC). San is the most general of these terms, the !Kung being only one sub-group of the San, but the !Kung are the most famous and well-studied of the San, and so they are often used as synonyms.
Political stuff: The !Kung had no form of government. They lived in small traveling groups in the middle of wide open spaces, with little or no competition for resources. Warfare (e.g. raiding parties) was limited to small scale skirmishes, and was carried out without the aid of any government. There are no chieftains or headmen, although there are, of course, some people who are more likely to be listened to than others. The men are not superior to the women, nor vice versa. There are healers, but the position is open to anyone who wants to learn (although it is more common for the males to be healers), and healers hold no mysterious powers. They also have no additional power over anyone because of their position.
An individual from an older generation will usually have 'authority' over younger individuals because of their age and experience, but this is not formally enforced. Because of this, the !Kung are sometimes used as an example of a functional and long lasting anarchical system. The fact that this mostly works because they are essentially permanently broke scavengers is generally skimmed over.
The !kung have a gift economy, meaning that instead of using money or barter, they give gifts. Since the !Kung are hunter-gatherers, they do not have much use for material possessions. The few things they carry with them can be manufactured by the individuals that use them, making formal trade unnecessary. Gifts are traded regularly (shell jewelry -- made from ostrich eggshells, not shellfish -- arrows, leather bags, etc.), but are of no real economic value -- instead, they form and cement social bonds. The one area where gift giving is important is meat.
Only the men hunt large game, and a large kill is an important source of protein (although not the only source -- Mongongo nuts also help). Because these kills are somewhat infrequent, and because a large animal (which may include giraffes and elephants) will give more food than a family needs, meat is given away to those in need. The meat is not distributed primarily on basis of need; the best and most meat goes to the hunters and their families. However, there are specific gift relationships known by the members of the group that allow a kill to spread throughout the group.
Where can I read more?!
Glad you asked. Here are some books that are worth reading. I'm sure that there are a lot more, but these I know are good.
The Dobe Ju/'hoansi by Richard B. Lee. A standard ethnography.
Boiling Energy by Richard Katz. The !Kung have frequent healing dances, where the dancers are possessed by a force known as num. These dances are the primary sources of healing, and are important social events. Read all about it here.
Nisa, The Life and Words of a !Kung Woman by Marjorie Shostak. Good biography. Also, a good description of what it's like for an anthropologist working in the field.
*The ! stands for an alveopalatal click. The !Kung language has a whole set of clicks and pops in it -- for example a Dental click (/), an Aveolar click, an Alveopalatal click (!), and a Lateral click (//). It also has a Glottal stop('), and a Glottal flap (").