During the BlizzCon 2013, Blizzard unveiled 3 videos regarding their upcoming MOBA Heroes of the Storm. They released a cinematic trailer, a developer interview and perhaps most importantly a gameplay demo that you can view below.
The free-to-play MOBA will allow players to become one of Blizzard IP characters. 16 heroes were available for testing during BlizzCon, with many more planned for the future. Heroes of the Storm will be starting beta soon. Everyone can sign up for the beta on the official site here.