League of Legends gets a lot of hype when it comes to professional gaming, but DOTA 2 has a very large following and a sweet tournament as well. Valve's Gabe Newell has just announced that they are chipping in $18 Million for the new DOTA 2 International Championship, so if you play, you should look into how to register your team to be part of the fray. For $18 Million, it's worth a shot - if you're any good at all. Good luck!
Dota 2 is a terribly addictive game and it makes for a fine competitive spectacle as well, judging by the viewer numbers it attracts on streaming services like Twitch. It isn't quite on the same level of popularity as the similar League of Legends - another team-based battle game where the goal is to destroy the enemy's base - but The International is certainly the most prominent tournament in the genre of competitive gaming.