And as a pet peeve of mine, the word Myth is tragically misused these days. It is supposed to stand for a story or account where the facts are false but they point to an even greater truth. A myth is the only way to convey truths in their pure form that don't exist perfectly in the world. For instance, the myth of Perseus never happened, and maybe there was never a Perseus at all. But the story illustrates things like courage better than any real story could.
These days myth is often used to mean "falsehood" or "lie", which is a shame because a) we already have those words, we don't need another, and b) when people encounter a real "myth", they approach it differently because of the word's new connotation.
Anyway, back to the subject at hand; I don't know of any good conspiracies. Milli Vanilli was lip-synching.