?? The Mayan calendar was chosen to end because of astronomy. Where it ends the solar system shows unusual alignment with the galactic center. The reason this is thought to be potentially catastrophic is because it may act as a lay-line for cosmic radiation/energy. Even modern astronomers and scientists can't accurately predict what will happen - but the Earth has survived several such cycles and I doubt it blew up each time.
Personally I doubt anything 'big' will happen, maybe some strange magnetic readings, maybe the poles (north and south) will get jarred a little. The real reason that the Mayan calendar is amazing to me is their mastery of mathematic equations and astronomy - we didn't have the instruments to accurately predict this kind of phenomena until less than 100 years ago.
Does it mean the world will end? The Mayans believed the current 'age' would end and the world would start another. It was tied into their religious beliefs - and sadly for them the Jesuits burned all of their books which outlined everything about it.
I don't know anything about ties to the lake Tahoe basin, but ignoring the astronomy factor and the overlying cause of these 'doom prophecies' is a big oversight. The Mayans were right in predicting the alignment, whether the religious aspect of it was correct remains to be seen.