Blizzard will be giving out beta keys for a mysterious new game at this years BlizzCon.
“We’ll be handing out plenty of Blizzard swag at BlizzCon for attendees to show off to their friends. However, we wanted to give out even more, so we’ll also be providing a beta key for an upcoming Blizzard game.”
The event takes place on August 3-4 at the Anaheim Convention Center in California.[Source]