This is my pony clock implanted as a windows gadget. Tested on Windows 7 64bit, but should work on every version.
Extract the PonyClock.gadget to c:\Program Files\Windows Sidebar\Gadgets
Right click on your desktop -> Gadgets -> Pony Clock and drag it wherever you want.
(Vista users might need to run that .bat file to update the register, not sure about this tho, I included it just in case).
It uses my previous uploaded image: [link]
EDIT: If anyone wants it in a different size (default is 200x200px), just leave a comment on how big you want it, and I'll fix it