1. Cut construction paper, card stock, or even regular paper into strips.
(You can either cut freehand, use a ruler to draw lines as a guide, or fold your paper like a little accordion and then cut down each fold.)
2. Fold the first strip into a circle and staple the ends together.
3. Fold the second strip through the circle you just made.
4. Make a circle with the second strip, stapling the ends together. Repeat until you've used all your strips.
5. Write a number of pi on each link in your paper chain. Here are some more digits to get you started: 3.14159265358979323846264338. (You can find a million digits at piday.org/million, but nobody has time for that!)