While generally agreeing with VT above, I would add that many people use the term "mythical national championship" in a positive way-
as in "We (Florida State) won the MNC."

The actual championship of college football in the United States is decided by a complicated payoff system, also known as the Bowl Championship Series, with little of that cash going to the players.

The BCS is the only "championship series" known to man that involves 10 teams and only playoff game.