Imagine you have a magnet. I mean, I'm sure you do, somewhere, but imagine the one you're imagining looks like this:
For our purposes of explaining, this is a perfect magnet;
Your magnet has a North Pole and a South Pole, and I bet you can tell which one is which. We've all played with magnets, and we all know what happens if you take two of them and try to stick the red North Poles together; they don't want to cooperate. On the other hand, North and South will happily attract while South and South will repel just like North and North.
Now imagine you have a compass, and your compass looks like this:
It's got the helpful red North and blue South just like our magnet from before.
You flip you compass open, the red North points off somewhere, and you find yourself confident that that direction is North. That is to say, your compass points toward the North-seeking Pole of the big magnet known as Earth.
But wait. Does it?
No, of course not; recall how North and North repel one another! The red magnetic North Pole of your magnet can't be pointing towards the magnetic North Pole of the Earth. That makes no sense. It's the magnetic North Pole of your magnet will be pointing towards the magnetic South Pole of the Earth (the magnetic South being the pole which seeks North!).
I mean, look at this nonsense:
Earth, with field lines flowing TO North FROM South
Every other magnet ever, with field lines flowing FROM North TO South
So we're left with a strange situation. We have the Earth, and it's definitely a big magnet. It has a North and a South Pole, and that's only because it was a magnet in the first place. But the magnetic North Pole of the magnet, Earth (i.e. the place we would call the North pole of any other magnet), is the location which Geographically we've termed The South Pole. Similarly, the magnetic South is that which we call the North Pole!
How did this happen? Long story short, it's just another one of those things. We've had compasses for a lot longer than we've understood magnetism, and clearly at some point we got a bit turned around. Imagine a scientist on mainland Europe giving compasses to sea captains. The scientist understands, but when the captain flips open his compass and sees there's an arrow labeled 'North', it's understandable that he thinks the direction it points in must be North.
Oh well. It's probably fine. We've made it this far.