Flexagons

Flexagons - Includes an introduction and history of Flexagons and a tutorial in how to make a Hexa-hexa-flexagon.
http://www.enarsson.nu/Flexagon/

Flexagons - 1962 technical report which includes an introduction to the history of Flexagons.
http://theory.lcs.mit.edu/~edemaine/flexagons/Conrad-Hartline-1962/

Flexagons - Contains instructions on how to fold a flexagon, history of flexagons and printable models of some.
http://www.geocities.com/CapeCanaveral/Hangar/7773/flexagon.html

Flexagon Re'flex'ions - Several possibly new trihexaflexagon phenomena are presented. The wide spectrum of findings including explorations with magic squares, palindromes, and much more freshly fans the flexagon fun.
http://hometown.aol.com/verndrei/flex00.html

Flexagons - Includes a definition of the word, instructions on how to make a Trihexaflexagon, how to flex it and information about it and another flexagon.
http://www.mathematische-basteleien.de/flexagons.htm

Hexaflexagon Toolkit - A free application that can generate a hexaflexagon template and folding instructions from six user selected images. Examples Source Code included.
http://hexaflexagon.sourceforge.net