No, seriously. Stop laughing. That's actually how they enter.
"Instead, Canadian residents may enter by submitting a 250 word typewritten essay comparing the video gaming culture in Canada to the video gaming culture in the United States on 8 ½ x 11 inch paper and mailing their essay to Essay Entry for The North American Blizzard Entertainment Arena Tournament, P.O Box 18979, Irvine, CA 92623." It's in section four of the legal for the tournament.
Apparently, according to the forums, people have called in and been told there is no payment option for Canadians, it's write the essay or nothing. Being somewhat of a stubborn cuss, I decided to call Blizzard myself and ask via the Billing and Account Services department. After spending some time on hold being creeped out by the Diablo music (seriously, I don't need to hear the 'Stay awhile and listen' music on the phone) a very helpful Blizzard rep explained to me that they would be happy to take my money to play in the tournament and that the essay is in fact optional.
Unless you live in Quebec, he said. It's illegal to enter any such contest there. So there you have it, Canucks! You can pay or write an essay as you choose, unless you're in Quebec, in which case your local laws force you to take the role of spectator.