Here's one I've never heard...http://en.wikipedia.org/wiki/Sedeprivationism
Sedeprivationism is an ideological school or party of the traditionalist Roman Catholic movement that holds that Popes since John XXIII have been defective Popes, following the principles of the late French theologian Michel Louis Guérard des Lauriers, O.P., as Lauriers set it out in his thesis published in the Cahiers du Cassiciacum and therefore called the "Cassiciacum thesis".
According to Laurier's thesis, Popes John XXIII, Paul VI, John Paul I, John Paul II and (implicitly) Benedict XVI and Francis were or are defective Popes in that, due to their supposed espousal of the "modernist heresy", their consent to become Pope was faulty or defective, so that they became potentially Pope, but did not attain to the papacy.
This idea is also described in another manner by saying that they became Pope materially but not formally (the formula, "papa materialiter non formaliter").
Two consequences flow out of this thesis:
There is no real sede vacante since a man fills the role of potential Pope;
If the current potential Pope recants from Modernism and returns to Catholicism, he will complete the process and attain to the fullness of the papacy.
The terms sedeprivationism and sedeprivationist were coined by the late English Sedevacantist William J. Morgan.
Besides the late bishop Michel Guerard des Lauriers, O.P., those Traditionalists prominent for subscribing to this explanation are: Bishops Robert F. McKenna, O.P. and Donald Sanborn in the U.S.A., and Fr. Francesco Ricossa and his Istituto Mater Bonii Consilii (alternative name Sodalitium Pianum), to which Bishop Geert Jan Stuyver belongs, located in Flanders as well as the cities of Turin and Rome in Italy.