Thanks to Jack and Wikipedia for this definition:
A conspiracy theory attributes the ultimate cause of an event or chain of events (usually political, social or historical events), or the concealment of such causes from public knowledge, to a secret and often deceptive plot by a group of powerful or influential people or organizations. Many conspiracy theories state that major events in history have been dominated by conspirators who manipulate political happenings from behind the scenes.
To explore this topic further: http://en.wikipedia.org/wiki/Conspiracy_theory
