Join the "Cheerfuls" contest and get a chance to win a Heart of the Swarm beta access.
What's a Cheerful?
Here are some examples and explanations of Cheerfuls:
Awesome! Where do I get in?
Here is a list of all the fansites hosting a "Cheerfuls" contest:
If you are looking for a contest in one of the other languages officially supported by Blizzard, please check the links below:
StarCraft II Source
StarCraft 2 France