Elves on New Year's Eve

New Year's Eve in Iceland

The magic of New Year’s Eve in Iceland is of course legendary. The Northern lights light up almost every night during winter and people admire them all around Iceland but this is probably the only night during the dark months of winter in Iceland when people really don’t care if the lights are due to make and appearance or not.
In Iceland the old year is blown away with bonfires and fireworks that light up the sky and the coming year is welcomed with continuous parties and food throughout the evening and into the early hours of the morning. The sight is a spectacle all of its own and accommodations in Reykjavik are sometimes fully booked weeks in advance because people are so psyched to see it.
On this night the Elves traditionally move houses, they change dwelling places. 
They can take up residence anywhere in any rock or stone or wall for that matter. 
Having a resident elf family close by can bring good fortune and so people are encouraged to welcome them into their homes or at least to pass through with the words:

Komi þeir sem koma vilja
Fari þeir sem fara vilja
Veri þeir sem vera vilja
Mér og mínum að meinlausu

The general meaning is something along these lines:
I honor those that here do pass
I bid them well who want to leave
I welcome those who wish to stay
But harm not me and mine