Re: Can I just say that Pi day is..
"355/113 is better yet, and manageable with 16bit integer arithmetic."
I have no doubt it is, but our year isn't that long. Neptune's year, on the other hand, can handle it: since it it lasts for 164.8 Earth years, it contains 75583.66 Neptunian days, which can fit 120 months of 360 days each with a lot of room to spare.
Uranus does nicely, too. Its year lasts for 84.07 Earth years, with a 17.9-hour day, giving 41142.64 Uranian days - 115 months of 360 days each with *some* room to spare.
Unsurprisingly, Pluto won't cooperate: its year lasts for 247.7 earth-years, with a day that's 6.39 Earth-days long, so its calendar only has 14148.75 Plutonian days.
So, we should be celebrating Pi Day on 22/7 on Earth, Mars, Jupiter and Saturn, and 355/113 on Uranus and Neptune. Pluto, since it won't cooperate, can go frack itself. I wonder if Sedna will be better?