I second DemocraticSPACE's call for the Green Party and Elizabeth May to be included in the national leaders' debate.
Greg puts it well:
The Greens are one of only 5 parties to receive public funding (about $1.2 million in 2006); Canadians deserve to hear what they are getting for their money. In 2006, the Greens won over 660,000 votes, about 1 in 20 votes, 24 times more than the next most populous party, so they can hardly be called “fringe”. They are polled by every pollster in Canada and have consistently maintained the support of about 1 in 10 Canadians since 2006. They are one of only 4 parties to run a full slate of candidates. And they now currently have an MP. By most objective metrics, the Greens should be included.