In Classical Chinese Medicine the body is governed by the operation of 12 organ networks that are active at different times of the day according to their differing physiological characteristics. For example, the Large Intestine represents the explosive energy of the sunrise. When you take a 24 hour day and divide it by 12 you get 2 hours per organ. But not really, because this method doesn't take into account the longer daylight hours during the summer and shorter daylight hours during the winter. What you really want is a clock that calibrates to this.
After talking with a couple of my teachers, and thinking it might be more clinically relevant to know which organ network was currently most active, I devised a widget for Mac OS X. It calculates sunrise and sunset based on a given location (longitude and latitude) and maps the current time to the energetics of the correct organ. Here's a sample:
Email me if you're interested in obtaining this. I'm offering lifetime support for $20. It requires Mac OS X 10.4 or above.