Yes it's real! Yes, I course it can play 3DS games.
To answer the rest of your questions, though please message the user 'Valwin'. He has all the details you'll need to set up this hack...
No, it was a 5,000+ year old Mayan prediction based upon their calendar that the world will end on the Summer (Winter if you're in the Northern Hemisphere) Solstice this year.
It's still a pile of crap, though...