This presentation is used as a precursor to my Geometry in the World Project (rubric available separately for free). It describes various geometric shapes along with postulates and theorems in one of our local historic cemeteries.
Students are then expected to create their own project using at least 5 postulates or theorems and 5 definitions from their textbooks (or whatever source you use).
My experience is that students typically enjoy the project so much that I usually get more than the requisite 10 examples.
This is a good way to get students to think about math in the environment and provide them with a creative outlet.
Geometry in a Cemetery Presentation is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License