According to their Facebook page: Welcome to Facebook - Log In, Sign Up or Learn More Alpharooms had a recent £300,000 giveaway. Seems to be over now though with lots of people complaining they either didn't get a voucher at all or they got one for just £5 Some people are giving away their vouchers though since it has to be used before they end of the year. However, they are in £'s so not sure it would work from Canada.
