There are hundreds of tournaments for these games across the world, but there are a few tournaments that are the most popular and the biggest in the world. Evolution (EVO) and Major League Gaming (MLG) holds some of the major tournaments, with thousands of participants, and even more spectators. Since technology has improved you don't physically have to be present to view these tournaments, and in the past years the tournaments being streamed has reached hundreds of thousands of viewers online.
Evolution
This tournament is held once a year on the same date: July 6-8 at Ceasars Palace in Las Vegas. It is the biggest fighting game tournament in the world, usually with over 5,000 entries into the tournament itself and thousands of spectators. It also gives the biggest prize for first place topping $50,000. Players from all over the world attend this tournament and people from all over the world watch the tournament live streamed on the internet. Upwards to 100,000 people tuned in to watch the tournament last year. It is the most anticipated tournament for fighting games and it's what other tournaments strive to be.
Major League Gaming
This League of gaming is very diverse in its selection of its games, ranging from first person shooters (FPS) like Call of duty to real time strategy (RTS) like Starcraft II. They hold tournaments for all their games and don't really have one big tournament, they have huge tournaments throughout the year. Their most popular tournaments are the ones involving games like Halo 3 and Call of Duty, but there are definitely others out there. Their prizes for first place are enormous since they are sponsored by big companies like Pepsi and Microsoft. First place prize money can range from $30,000 to %500,000 dollars, all provided by the sponsors of the tournament. They also stream all of the tournaments they hold and people can spectate by whichever means they feel easiest. If you visit their site MLG you can find information on upcoming tournaments and events.
It's a montage of Halo 3 by one of players in MlG. All of the clips are tournament footage.
