Great Debate tickets are already on sale. Along with various other shows -
http://www.comedyfestival.com.au/shop/
I'm a little annoyed, I've been checking the site for ages, keeping an eye on the debate to see if tickets were up yet, and they didn't officially announce them going on sale, just that they were already available. The main page for the debate doesn't have a link to buy them or anything either. I only found out because of the email that went out today.
I'm also still dubious about the Gala being at the Vodafone Arena this year...very rarely can comedy successfully be an "arena spectacular"...