This StarCraft II mod is a whole new game
This giant mod is really a whole new game built with StarCraft II's tool set. It's a masively-multiplayer online game featuring classes, character customization with skills and abilities, raids for players to tackle together, and player vs. player content if you don't feel like working together.
StarCraft Universe will be free to play if you own StarCraft II. Just search for it on Battle.net in the mod section.