If you have a bar magnet (shaped like a rectangle), make a mark on one end of your magnet. Now tie a string in the middle of your magnet, hang it from something, and watch what happens. The magnet will rotate around until the north-seeking pole points to the north and the south-seeking pole points to the south; this is how the poles got their names.
If you know the general direction of north and south from your house, you will be able to figure out which end of the magnet is pointing north and which is pointing south.