(Image courtesy of http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html)

It is important to note that earth's true magnetic north (the pole that attracts the south pole) isn't the geographical north pole. As http://deeptow.whoi.edu/northpole.html says "Earth's magnetic north pole is where the magnetic field lines are oriented vertically and plunge into the surface of the earth". We know that the field lines travel from north to south, so it must be that the earths geographical magnetic north is true magnetic south. In the picture below the exact location of earths geographical north magnetic pole. Located in northern Canada.

(Image courtesy of http://antwrp.gsfc.nasa.gov/apod/ap020818.html)

Although this can seem weird at first it makes logical sense to call it the "north pole". Think of a compass for example. The needle "points" to the north pole. What is really happening is the metal in the compass needle is being attracted to the earth's magnetic south pole. It is easier to think of pointing north=north, instead of actually understanding the compass isn't pointing, but instead being pulled.

There has been talk that the magnetic fields have swapped before. This information can be found here.

The earth's magnetic fields and the Van Allen radiation belts are the cause of the Aurora.(Pictured below)

(Image Courtesy of MIKE KUDENOV; Note: this image is a much smaller version than the original)

"The Van Allen radiation belts consist of charged particles (mostly electrons and protons) surrounding the Earth in doughnut-shaped regions" (Serway). These particles are trapped by Earth's magnetic field. The Van Allen belts "spiral around the field lines from pole to pole..."(Serway).The cause for the aurora is particles colliding with atoms in the atmosphere. The reason the Aurora is mostly confined to the polar regions is because this is where the Van Allen belts are closest to the Earth's surface. The Earth's surface is where the field lines enter or exit the planet. It is at this location where the Van Allen belts interact with the Earth's atmosphere causing the collisions discussed above.

This picture shows where the two Van Allen belts are.

(Images Courtesy of http://csep10.phys.utk.edu/astr161/lect/earth/magnetic.html)

This picture shows the Van Allen belt's spirals and the field lines.

As you can now hopefully see magnetic fields not only play a role in physics but are also very applicable to our everyday lives. Magnetic fields are very complex and I've only touched the surface. For more information please try these sites 1, 2.