I think this music event is going to be incredible all on its own, but they are also running a few contests in support of the online ticket sales. On MovieTickets.com, if you purchase a ticket for Halloween night, you are entered to win a prize package (poster, soundtrack, t-shirt, and ticket from the tour.)
I think Halloween is going to be the best night to go see this, actually, because I have read that people are planning to dress up in tribute of Michael. It should be a really amazing thing to see, and let's face it, I am going to love seeing the costumes!!