My favorite teaching tool the way Pythagoras created it!  I prefer the one where ii-V-I run clockwise but this one is the most common (at the moment) so I wanted to make it available too.  
 
Make your own movable Circle of Fifths.  Download as a PDF right away.
 
Watch a short video to see how it goes together 
 
The original Pythagoras Circle of Fifths (over 2,000 years ago) shows frequencies so the circle runs the opposite way.  This circle orientated the original way but music moves from V - I and I have another circle shows is oriented the way music moves - as a clockwise movement.  It is also a Circle of 5ths because C is the 5th of F which is the 5th of Bflat, etc. etc.  (too much information?)