Sunset Times is a very simple project that has all the years sunrise and sunset times, it also has the daytime length. The data is all held in a wordpress custom type which is easily administer-able is required.
There is also a cron job on this site that generates a tweet and updates this users twitter feed (https://twitter.com/sunsettimesuk) every day with the days sunrise and sunset times.
We have also created a wordpress plugin and API for this feed so if anyone wanted to install this widget on their site they could within a few minutes, the widget only calls the API service once a day and it caches that response for that whole of that day, this means less load on the servers.
