Click on photos below to see a larger version.
The head is constructed out of a hockey helmet, solid steel wire, plastic mesh, and lots, and LOTS of Zip-Ties..
My human jaw fits on the back of her 'foam and vinyl tongue' and that causes her mouth to open.
The jaw closes with a wire spring attached to the side of her jaw (which is pretty invisible)
Legend helped me with eyes for Diadexxus. We used the same process as we did with the Gryphon, and I never fog up.
Actually its not that difficult to do. Get some ink-jet printable Mylar (clear / transparency sheets), and design your eye in photoshop or Bryce (as mine was). REMEMBER, Irises (the colored part) are not all one color! Add some other colors into it, will add character!
Before printing, fit them on a sheet (I think you can fit like 8 on a sheet), Cut one eye out square. Cut one eyeball square off the mylar. (dont cut it round yet!!) What we did is fanaggled a cutter-board on the end of a drillbit to hold the square-cut mylar. We attached the square-cut mylar to the cardboard we had holding on the bit. Took a Xacto knife and then spun the drillbit slowly and cut the iris (colored part) out first, then the pupil. (this second part can be skipped and you can just x- acto knife the circles with a stencil of some sort.)
Then, we attached the cut eyeball to some fine mesh. I painted the pupil black. The hardest part was cutting a cheap plastic champagne glass to get the eye-cover even on both sides. Voila, pretty eye!