Tomorrow December 21st, 2012 a very long Maya calendric "cycle" - that lasted over 5000 years - is coming to its completion! At the same time tomorrow (by coincidence? If it's not a coincidence then we have to admit that the Maya had an "ultra advanced" knowledge of astronomy) a VERY IMPORTANT cosmic alignment will occur between the Earth, the Sun and the Center of our Galaxy.
On its own, this cosmic alignment (which ultimately is not that accurate) does not portend a major catastrophe for humanity. Almost the same cosmic alignment occurred in the previous 10-12 years (on December 21st) and nothing happened to Earth (not to mention that many scientists argue that the true, as accurate as possible cosmic alignment occurred back in 1998)!
In his (pdf) booklet: "An Essential Guide to the December 21st, 2012 phenomena" author Thomas Gazis is explaining in a clear manner all the phenomena associated with the tomorrow's "end" date . He reveals the deeper psychological meaning of December 21st, 2012 and he analyzes a rather strange astronomical phenomenon: tomorrow the planets Venus, Mercury and the Sun - and largely all the known to the ancient people planets - will rise in our sky almost in the same sequence they had risen in the "base date" of the Mayan calendar (on 11 August 3114 BC, that is). Meaning that in the very first day and in the very last day of the marvelous "Long Count" Mayan calendar a quite similar planetary configuration is taking place in the sky! Since the Maya were excellent astronomers we're not sure at all this is a pure "coincidence"...