Actually, 11 demensions is a facet of M-theory, which seems to have more respect than any other GUT out there.
Spinster: I believe the initial appeal of the many worlds theory came from a handfull of jerks (whose name I forget at the moment) who couldn't live with a quantum mechanical aspect of some particle having 40% matter waves that can't be atoned for anywhere by consistent observation, so they threw out the idea that they are manifested in parallel multiverses. On paper this also works well to explain how interference patterns are obtained in light-slit experiments when the intensity is reduced to one photon roughly every eight seconds. Granted that's totally a "what the fucking hell?" kind of result, I don't see it as requiring an outlandish conclusion.
I really should have studied for my physics test, which incidentally had a question on light slit interference phenomena. Yeah,