Pokemon Omega Ruby and Alpha Sapphire players have a good reason to play this weekend: a free Legendary Pokemon.
Depending on whether you own Omega Ruby or Alpha Sapphire, you earned either Latios or Latias during the campaign. However, you didn't have an opportunity to get the other Pokemon. That will change once you get a special item called the Eon Ticket.
To get Latios/Latias for your collection, choose "Mystery Gift" on the main menu of your game and then "Receive Gift." If your 3DS is connected to the Internet, you'll be able to select "Get With Code." You'll input one of the following codes depending on where you live:
When you talk to the woman, she'll give you an Eon Ticket. You have to then take this ticket to your dad at the Petalburg Gym. He'll bring you to a ship that will then whisk you off to Southern Island.
In the island's forest, you'll find either Latios or Latias waiting for you. When you catch the Pokemon, you'll also acquire a Soul Dew. This item boosts Latias/Latios' Special Attack and Special Defense when held. Once you've caught the Pokemon and left the island, you'll never be able to return.
If you don't use the code this weekend, there's an alternate way to get an Eon Ticket. If you have StreetPass enabled on your 3DS or 2DS, you'll be able to acquire the ticket from any players who have it.
StreetPass was how many players received the Eon Ticket in the past. Nintendo gave codes to Play! Pokemon League Leaders to distribute during their events last fall. The Nintendo World Store in New York City was giving them out until January as well. If you received the Eon Ticket previously, you won't be able to use the code above - which shouldn't matter because you won't need it anymore.