The United Federation of Independent Democratically Governed City States

A union of city states, each of which has a population of one.
http://www.student.unimelb.edu.au/~strauss/

The Republic of Lucastan

Founded in 1945 on a Pacific island won in a poker game.
http://www.keyflux.com/lucastan/

The Principality of Snake Hill

Information about the micronation that seceded from Australia on 2 September 2003.
http://members.lycos.co.uk/snakehill/

The Principality of New Pacific

Libertarian monarchy with executive, legislative, and judiciary branches.
http://www.geocities.com/newpacificembassy/