Pre-Cut Paper Circles...WCYDWT?

Oh the possibilities of these pre-cut circles... I found these last week at Michaels Arts & Crafts for $5.99.  Middle School OCD said she found a pack of 100 at Lakeshore Learning for around $4 a few years back.  I looked in their store in Tampa last week and couldn't find them.  They also don't carry it on their website.

This year (and two years ago), I used paper plates (the cheap, unwaxed ones) and had my students demonstrate their new vocab and labeling of a circle.  Here's the activity and the picture of them hanging on 2 clotheslines the width of my room (60+ students/plates).  The 9 backwards plates on the left are waiting for absent students...

I think this coming year I will use these circles and display them temporarily before having students place them into the INB.  If they put them in their INB, I won't be able to have them use the back...just a thought...

Middle School OCD uses them as a hands-on activity to show diameter, radius, circumference and area on one circle.  On another circle, she demonstrates complementary, supplementary and vertical angles.

My ideas:
GEOM - central angles and their intercepted arcs, inscribed angles and their intercepted arcs, area of sector and circle, arc length and circumference, right triangles inscribed in a semicircle, cyclic quadrilaterals, discovering pi using circumference and diameter,

TRIG - unit circle - radians, degrees and coordinates

I'm probably going to have to make a trip back to Michaels because I have more ideas than circles!!
I will keep thinking... Leave me a comment if you have any suggestions!