Goblins are wandering sprites who like to live in grottoes, and also in the homes of humans (particularly those that have beautiful children and lots of wine). They will move into a household and aid the occupants by doing the chores at night time, and by disciplining the kiddies - punishing them when they are naughty and giving them gifts when they are good (I would tend to behave if I had some bizarre mystical creature living with me...).
The idea of a live in other-wordly housekeeper may appeal, but be warned - goblins possess a mischievous, unpredictable nature. They are just as likely to clean your dishes as they are to move your furniture, knock on walls and doors, bang on pots and pans, snatch off your bed sheets, and generally create a big old ruckus during the night. If you housed a goblin who, despite all his cleaning capabilities you wanted no longer, you could spread flaxseed on the floor - the little guy will leave because his obssessive-compulsive cleaning means he HAS to pick it up...and he'll tire of it soon enough.
Through time goblins have become associatted with Halloween, and are rumoured to roam on that night (when the world of the dead and the world of the living are closest). That would be the ideal night to entice the little sprite to stay...
Goblins are found primarily in French folklore, and are the equivalent of England's brownie, Germany's kobald, and the domoviks of Russia.