Unless you've been living in the Dalaran sewers, you've probably heard about a little game called League of Legends by Riot Games. What many folks don't seem to realize, however, is that its gameplay is based on an old Warcraft 3 mod called "Defense of the Ancients." DotA, as it was called, nearly single-handedly popularized the multi-player online battle arena (MOBA) genre, and the rest is history.