I was on the hunt today for a clock application and ran across an interesting implementation in Wallpaper Clock. Basically it's a small application that dynamically redraws your Desktop every minute, to keep your time and date, well, up-to-date. The application itself is free, but requires particular artwork files in a variety of designs. Some of these clock files are available in a free, low-quality version, while others are only available to registered users (along with the free ones in higher-quality versions). It is also possible to create your own Wallpaper Clocks with your own images.
Wallpaper Clocks is a free download however there is a registration fee for subscription based access to the maker's website with artwork unavailable in the free version. Subscriptions are $8.99 for 3 months, $12.99 for 6 months, $19.99 for one year, and $29.99 for lifetime access.