No, it's not the study of gnomes.
There is a dull, barren triangle across the street from our house and I am trying to convince the city to let me build a sundial there. I emailed them, they emailed me back and are ready to set up a meeting with me and as many of my neighbors as I can drag with me. Now that they've called my bluff, I'm in the process of learning how to build one.
There are lotsa different kinds, and you can get lost in the details fairly quickly. The easiest to build would be the one pictured above: find true north, put up the pole (it's called a "gnomon") at the appropriate angle, pour the concrete, measure the angles and put down the marker lines. You can get the angles for your latitude at many different sites.
The one above is the one I'm gonna push for. A human sundial! You stand on the month, and your shadow tells you the time! Much cooler, but the process is quite a bit more complex, as you've got to figure out the standing positions for each month, and I can't quite figure that part out yet. There are companies out there who will sell you the layout, but no place I've found that will allow you to calculate the values themselves.
Here's a picture of a finished one.
Of course, were I a little more ambitious, I'd build me one of these.
Anyone have an idea of how to calculate positions for the human sundial (I think they are called "analemmatic" sundials), gimme a shout.