We had someone recently ask about human sundials on our Facebook page so I thought I'd shed a little light on the concept (bad pun I know). Of course we're all sundial gnomons (aka sundial pointer) when the sun's rays hit us and a shadow is cast on the ground. The key to turning us into a working sundial is just similar to constructing a sundial out of any material. The hours need to be laid out in a pattern and directed towards true north. You could use anything from sticks coming out of the ground to more elaborate ways to mark the numbers such as stone or mosaic. This seems like a great project for schools to try.
If you don't want to make your own human sundial and find yourself driving through the Georgian Bay region of Canada, stop at the Keppel Croft Gardens. Not only do they have a beautiful example of human sundial (see photo below), but they have also designed and constructed their very own megalith circle. Named Keppel Henge, it features a tall granite stone that casts a shadown on limestone megaliths at different times of the year (equinox and solstice).
How Keppel Croft Gardens built their Human Sundial - http://www.steveirvine.com/sundial.html