The arctic circle moves?

Yes - I believe this is true. The positions of the Great Circles are not fixed. Their exact locations are relative to the Earth's axial tilt (obliquity). The axial tilt fluctuates within a margin of about 2° over a 40,000 year period. If it weren't for the Moon, this degree of fluctuation would be even greater. I've seen latitude values from different Epochs, but not on a yearly basis although I'm sure it exists. That said, I think we're talking about tenths, hundredths, or thousandths of a degree difference so it's not a radical movement.

I had no idea it moved either!

http://en.wikipedia.org/wiki/Arctic_Circle

The position of the Arctic Circle is not fixed, but directly depends on the Earth's axial tilt, which fluctuates within a margin of 2° over a 40,000 year period,[2] notably due to tidal forces resulting from the orbit of the Moon. The Arctic Circle is currently drifting northwards at a speed of about 15 m (49 ft) per year, see Circle of latitude for more information.