I was under the impression that Quebec still had a Charter of Rights notwithstanding clause in effect to allow its language law. However, I was wrong. The Charte de la langue française was modified in 1993 to require that French be predominant on outdoor commercial signs. The government did not invoke the notwithstanding clause for the new version of the law.
That would certainly explain how Stéphane Dion can defend Quebec's new and improved language law.
Amazingly, there is currently no legislation in effect, federally or provincially, that uses the notwithstanding clause.
More about the notwithstanding clause from the CBC (excellent).
Since the clause can be used every 5 years, I suspect that it is quite likely that a Conservative majority would use it to outlaw same sex marriage.
I like the notwithstanding clause. It puts democracy first while keeping a nagging reminder that you are violating Charter rights.