Due to the release of the third and last part of the comic trilogy The Promise, which is available in comic shops on Wed 9/26 and in bookstores on Tue 10/9, its author, Gene Yang, has created a contest in Twitter. You only need a retweet to participate for the prizes, which are:

• A Lego Aang minifig
• A Lego Katara minifig
• Two minifig stands
• A bookplate (i.e. sticker for the inside cover of your copy of A:TLA – The Promise Part 3) with a personalized message and Gene Yang's signature.

You can read more in Gene Yang's website.