http://en.wikipedia.org/wiki/Delaunay_triangulation
It appears they are using https://github.com/GianlucaGuarini/site-under-construction/b...
http://codepen.io/GianlucaGuarini/pen/sJgnh
And at least some of the animation (maybe all) with TweenMax http://www.greensock.com/tweenmax/
Full JS from F8 https://friendpaste.com/57YBk1KFHY16AsClrqQDZL
Also, the geometric backgrounds on this site are beautiful. Would love to know how they implemented those!