I have a friend who plays an online game called League of Legends.
He is very good at the game and is ranked very high.
This is a free game, has been around for only 2 years, and has become very competitive.
Hundreds of thousands of people have started to play (mainly because it's free and an awesome game)
This friend started streaming his games on a site called Own3d.... While streaming the game he gives tips on how to play, has conversations with other friends who play (on skype), and is able to put up advertisements through own3d.
Once he started making money he created a website so people can easily watch him stream....Then allowed other people to put their streams on his site.
His site generates thousands of dollars a month just from visitors... Plus he makes over $3,000 a week from streaming on own3d.
I know a lot of people who stream on justintv and other sites and make a lot of money from sponsorship and advertisements.
There are hundreds of different games that people stream and make money from (as long of course as you have viewers)....
The sad fact is that you don't have to be great at a game to have viewers.. There is an ex-porn star who streams games.... (there is a feature where you can show yourself in the bottom right when streaming the game)... She gets tons of viewers.... People chat with her while she plays.
Anyway.. there are thousands of streamers around the world making money by just playing games. That is their job.
I hope this thread inspired somebody.