Well the Mayans may have gotten the date but Aztecan belief states that we are in the Fifth Age or the Age of the Ollintonatiuh, the sun. They came up with the description of what happens during the lasts days and surprisingly or maybe coincidence the descriptions are similar to certain events that are predicted in the Bible. Aztecan belief goes along the line that there would be a giant earthquake that would swallow the earth and disease a pestilence and there is silence.
Coincidence maybe to certain things in Revelation but what is consistent is that peopl never stop coming up with ways of predicting how the world will end. Mayans I could probably accept more readily than the alien spaceship theory in that they wer master mathematicians and could predict the occurences of Venus' appearance, etc. with astounding accuracy that makes our "superior" Julian calendar look pathetic.