The official Pokémon website has announced a new huge side event that takes place from August 21st, 2015 until August 23rd, 2015 alongside the 2015 Pokémon World Championships festivities. The World Championships streaming has also been announced. Full details are below.

Press Release - Compete in the Boston Open!

Lots of Championship Points are at stake in the Boston Open during World Championships Weekend!

Come play in the Boston Open, a huge side event for Pokémon TCG and video game players starting Saturday, August 22, alongside the 2015 Pokémon World Championships! A lot is on the line, with top players earning Championship Points toward an invitation to the 2016 Pokémon World Championships. Top finishers will also earn Pokémon TCG booster packs.

The competition is played with the Standard format for both Pokémon TCG and video game players. Note that the Pokémon TCG competition will use the 2015 Play! Pokémon season rotation. Competitors will be grouped into four flights, each with up to 128 Masters, 64 Senior, and 64 Junior Division players. Top players from each flight will combine to play in single-elimination rounds on Sunday morning. The Championship Points distribution will be the same as a Regional Championships event, and will count toward the Regionals Best Finish Limit.

Anyone can play in the Boston Open, but demand will be high and space is limited. Players must register on site to participate in the competition. Registration will be available from 9:30–10:30 a.m. Saturday for the video game event, and 7–8 p.m. Friday and 8:30–9 a.m. Saturday for the TCG event.

Live Streaming Schedule

Friday, August 21st, 2015
9:00 a.m. EDT - Opening Ceremony
9:30 a.m. EDT - 3:00 p.m. EDT - Pokémon Video Game Streaming
3:00 p.m. EDT - Finish - Pokémon TCG Streaming

Saturday, August 22nd, 2015
9:00 a.m. EDT - 12:00 p.m. EDT - Pokémon TCG Streaming
12:00 p.m. EDT - 6:00 p.m. EDT - Pokémon Video Game Streaming
6:00 p.m. EDT - Finish - Pokémon TCG Streaming

Sunday, August 23rd, 2015
9:00 a.m. EDT - 3:00 p.m. EDT - Pokémon TCG Finals (Junior, Senior, and Masters Division)

Sources: http://www.pokemon.com/us/play-pokemon/worlds/2015/boston-open/ and http://www.pokemon.com/us/play-pokemon/worlds/2015/live-streaming-schedule/