MEATHEREDOTCOM  I don't think I'm revealing any great secret here, as just looking at the first few bytes of the file gives away the file type. Anyway, making clocks of your own looks relatively easy, though may take a lot of time. The .wcz file format is just a renamed .zip file (wcz=WallpaperClockZip?). Change the extension of a clock you like and unzip. You'll see a long list of mostly .png files, labeled by function (e.g. moonphase1,moonphase2, etc.), each with a small graphic in the correct location to build the overall background image. Make your own version of each graphic, edit the .ini file (also in the unzipped folder above), zip them up, and rename. You should be good to go.  
(Version 1.0)

MEATHEREDOTCOM  Weird program. I had hoped that it would allow one to draw a graph by overlaying scanned data, enabling the extraction of data from research articles (or even the NYTimes), but I can't seem to find such a feature.

While it's easy to put multiple lines on a single chart, and easy to add various additional information, the program is limited to 2D point and line data (I know the description says it's ideal for 2-D graphing tasks, but for $30, I expect a little more).  
(Version 1.4.8)