League of Legends is from the original creator of DotA. It will eventually be a free to play sort of deal when it comes out. Then theres Heroes of Newerth from S2 Games (makers of the Savage FPS/RTS games), which basically got permission from the current DotA maintainer IceFrog to clone the game entirely, but on a new shiny engine.
And now IceFrog is working on something at Valve.