There is this lady, Vi Hart, who makes these really enjoyable and quirky videos about math.  They teach you some cool stuff about math in the world and her voice sounds like she is 17 so I constantly wonder how dumb I am listening to her.

Anyway, she does some cool and amazing demonstrations of math.  I don't have a favorite but I thought these two videos, which are part one and two of a series, would be both entertaining and fun for my daughters thus they are getting a special post here.  So, without any further ado I present Vi Hart talking about Hexaflexagons.  They are pretty bad ass.

Part 1

Part 2

Anyway it would be cool if you made a hexaflexagon and shared a photo of it - or better a video as a response to Vi Hart's; I bet she'd get a kick out of seeing folks building these and discovering some of their cool properties.