League of Legends

League of Legends has had to overcome a lot of obstacles in order to be successful. For starters, the game it's closely based off of (Defense of the Ancients) had an established audience, a lot of content, and a pre-established system of complex rules and techniques. But thanks to an art style that kept everything visually distinct, and thanks to the fact that League of Legends was free-to-play, an otherwise very hardcore game has attracted a massive audience. It's also very fun, and constantly updated with new Champions, and although the community is harsh, Riot seems devoted to making sure even the lowliest of noobs can have a good time.