The official Pokémon website has revealed that the first ever
Pokémon Game Show (ポケモンゲームショー) will be held at Tokyo Big Site (東京ビッグサイト) August 17th, 2013 and August 18th, 2013. Admission is free to the event.
The event will also have playable demos of Pokémon X and Y. People can also play the Pokémon Trading Card game and Pokémon Tretta.
Source:
http://www.pokemon.co.jp/info/2013/06/130628_g01.html