Hexaflexagons - How amazing is this paper folding?

What is a hexaflexagon? A strip of paper, folded into triangles that can do some really cool flips!

Cool videos:

• Vi Hart video about Hexaflexagons 
• Vi Hart video about Hexaflexagons, Part 2 
• Vi Hart Hexaflexagon Safety Guide
• Vi Hart Flex Mex
• Vi Hart - How to Make a Tri-Hexaflexagon (advanced method) 

Written instructions and templates:

• Instructions for making tri-hexaflexagon
• Flexagon.net The biggest collection of flexagon facts and fun!
• Aunt Annie's Crafts - good hexa-hexaflexagon templates