Pokémon trainers can now register for the 2015 International Challenge June Online Competition with their copies of Omega Ruby & Alpha Sapphire.
Your team of Pokémon must have been acquired in Pokémon X, Pokémon Y, Pokémon Omega Ruby, or Pokémon Alpha Sapphire. All Pokémon above Lv. 50 will be set to Lv. 50 for the duration of the battles. […] The competition goes from Friday, June 26, 2015, at 00:00 UTC until Sunday, June 28, 2015, at 23:59 UTC. Trainers will be limited in the number of battles they can compete in per day. Check out the 2015 International Challenge June Online Competition regulations page for complete details on this exciting event.
Through the competition players can also earn Championship Points which can earn an invitation to the the Pokémon World Championships.