Oh, I thought I had written that there was a 5-year term limit (only once extended, in 1916), but I guess in my edits, I took it out. Thanks for mentioning that, Gundark. But, Gundark, recall that our previous election had been in Nov 2000, and then, just over three years later, in April 2004, Martin called for another. The five-year limit wasn't even close, but Martin felt that he should be elected, rather than just succeeding Chretien, and also thought there should be an election after the Auditor General's report.

And the latest we would possibly have an election is in the spring, as Martin has promised to call an election within 30 days of Gomery's final report, to be released in February.

For a really quick overview, the Wikipedia page on Politics in Canada is very concise. I recommend.