I guess I do ask for money for this, but it's pretty overengineered and I wrote it knowing that nobody wanted or needed it:
Long ago, when Sun workstations were new and exciting, I wrote a simple Roman numeral digital clock, which just showed the time in Roman numerals.
My friend, instead of admiring my cleverness, said "But that's not how the Romans told the time" - which is true. The Roman day started at dawn and finished at sunset, which meant that day and night length were different every single day, as well as in cities at different latitudes.
Several decades later I did something about it, and wrote it up as a mobile app which showed either the modern time or optionally the Roman time.
Then I made it use the Roman calendar, where you don't have individually numbered days of the month, but count instead how many days until the next Kalends (start of the month), Nones (fifth or seventh day) or Nones (thirteenth or fifteenth day), even if it occurs in the next month.
Then I thought I might as well go all the way, and spent more money than I would ever earn from it on having the help text translated into Latin, just in case any ancient Roman time travellers wanted to use it.
A waste of time and money, but one which made me happy.
http://www.teapot7.com/roman-clock-app/