Some things people haven't mentionned yet...
It's considered impolite and dangerous to add wood to the fire before asking the igloo's owner permission first. You have no ideas how many igloos have been melted this way by unsuspecting foreigners.
If you feel like playing with sled dogs, you need to pet the alpha male first to avoid getting bit.
Penguins are actually much more dangerous than polar bears, especially when they have youngs to feed. Whatever you do, stay away from the penguins!
Most canadians won't be terribly offended if you burn a canadian flag, especially if it's to warm yourself. But if you want to make friends, it's best to burn Quebec's flag, except of course if you're in Quebec, where the opposite is true.
You'll need four sets of clothing, one for each season.
And finally, differences between americans and canadians are greatly over-exagerated.
I wish you a nice stay, eh.
I apologize in advance to anyone offended by my lame attempt at humor.