The first event runs from the 13th of October until the 26th of October and gives players the chance to get their hands on a Shiny Gengar holding its Mega Stone, the Gengarite.
From the 27th of October until the 16th of November GameStop stores will also be giving players their very first chance to get their hands on Diancie in Pokémon X and Pokémon Y.
No news on the distributions have been revealed for Europe, but we should be getting Diancie at least sometime soon.