Just add a skill testing question and you can also make this available to canadians!
there are laws that prevent companies or organizations for requiring people to sing up for somehting inorder to enter a contest to win something. so you can get around it by having a contest that allows you to answer a math question, and answering the math question correctly is actually what wins you the prize... most canadian will notice this, that winning most contests in Canada requires you to answer a "Skill testing question"... its a very simple work around, which would open the contest up to more of your loyal subscribers