Today was the day people have been joking about. At some point, it was decided that the Mayans had predicted today was the end of the world. The fact that they did no such thing was completely irrelevant to the joke. In having our fun with the joke, the Mayan's actual prediction appears to have gone unnoticed by most.
The Mayans were very interested in astronomy, and they were quite good at it for people who didn't even have telescopes. They also made complicated calendars. As everyone is aware, today was a big day on that calendar. Today is 184.108.40.206.0, the first day of a new piktun (the Mayan Long Count or 20 b'ak'tuns), and it fell right on the Solstice.
Instead of freaking out about fabricated claims about an apocalypse that they didn't even predict, we could have been focusing on appreciating that an ancient civilization created a calendar period more than 5,000 years long that landed directly on both the Winter Solstice and a day when "the sun will align with the center of the Milky Way galaxy".
Some folks certainly had some fun today at Stonehenge, another example of the amazing things ancient cultures could predict using the stars.
I wonder if those civilizations had people denying astronomy the way Creationists today deny Evolution.