Happy October, Month of the Hexaflexagon!
Oct.
21st is the annual Celebration of Mind, in honor of Martin Gardner.
This video is based on, and in honor of, Martin Gardner's column from 1956, "Hexaflexagons," which can be found here: http://maa.org/pubs/focus/Gardner_Hexaflexagons12_1956.pdf

Historical
Note: This video is based on a true story. Arthur H. Stone invented the
Hexaflexagon and started a flexagon committee with his friends
Tuckerman, Feynman, and Tukey (who all later became well-known in their
respective fields). Tuckerman invented the Tuckerman Traverse, and
Feynman invented Feynman Diagrams (not to be confused with Feynman
Diagrams in physics, which is probably why flexagon diagrams are usually
not called Feynman Diagrams anymore). The details of their interactions
and dialogue, however, are my own invention.

-Feynman stuff is from the biography "Genius," by James Gleik, p. 103-104
-The
story of how Gardner learned about flexagons is from "An interview with
Martin Gardner" in the June/July 2005 Notices of the AMS, p. 602-611
-Other historical information, including the text and names on some of the letters, are from Gardner's original article: http://maa.org/pubs/focus/Gardner_Hexaflexagons12_1956.pdf


Also
check out flexagon.net, a pretty good resource for patterns for
flexagons of many types, and of course the wikipedia page on flexagons: http://en.wikipedia.org/wiki/Flexagon