Making a icosahedron, a 20-sided shaped, out of paper is a fun project for kids or adults.
Things You'll Need
string or twist ties
Cut out 20 equilateral triangles from thick paper. The bigger your triangles the bigger your final icosahedron. Try and make all your triangles exactly the same; making and using a template is good idea. The more uniform your triangles the better your final icosahedron will fit together.
Using the hole punch, punch holes into the three ends of each triangle. Try and punch the holes in the same spot in triangle, and don't punch too close to the end of the paper.
Using the string or twist ties, connect four triangles together to a create a parallelogram. Repeat this 4 times - so you will have 5 parallelograms total.
Connect the parallelograms together by the middle triangles. See attached image (from the Geometry Center - UMN).
Carefully "roll" up the triangles and attach them all together to get your icosahedron! Enjoy!
Try to make as perfect a equilateral triangle as possible as your template. You can color the pieces to make it more decorative The Geometry Center, part of the University of Minnesota is a great place to go for more Math Fun
You may find out that math is fun and vindicate your grade school math teacher's dorky proclamations.