Felix Kjellberg has more than 25 million subscribers on YouTube, more than 3.8 billion views on his videos, and has made millions of dollars in advertising revenue — all for recording himself playing video games and providing running commentary. If you haven't come across Kjellberg, or PewDiePie, as he's known on YouTube, this montage is a good introduction. And if you want to learn more about Kjellberg, his fellow gamers in the so-called "Let's Play" genre, and YouTube gaming as a full-time job, read this story by Christopher Zoia in The Atlantic.