When is the last day to get an original Eon Ticket in ORAS in America?

Question

I really need to know, because I will only be able to get the game for Christmas.

Answer 1

The event lasts till January 14th, 2015 ([source][1])

If you're planning on getting the game later, don't worry, you've got plenty of time.
[1]: http://www.pokemon.com/us/pokemon-news/get-the-eon-ticket-via-streetpass/